Nomenclature — entries 535
Design Nomenclature
An illustrated encyclopedia of the words designers use — colour, type, and composition on the flat, through form, surface, and light, to the language of the shop and the modeling package. Every entry is defined, illustrated, and set against the terms it is routinely confused with.
Color
Harmony, contrast, appearance, and the models used to specify and mix color.
Type
Letterform anatomy, classification, metrics, spacing, and typographic composition.
Composition
Gestalt, grids, balance, figure and ground — how flat elements organize on a surface.
Form & Geometry
Primitives, topology, curvature, and the vocabulary of three-dimensional form.
Surface & Material
Texture, finish, reflectance, and the physically-based vocabulary of materials.
Light & Optics
Light types, shadow terms, and the language of rendering and photographic form.
Digital Model Making
Modeling paradigms, mesh operations, sculpting, parametric and generative methods.
Physical Model Making
Subtractive, additive, forming, casting, and joining — the vocabulary of the shop.
Systems & Spec
Measurement, tolerance, accessibility, and the conventions of specifying work.
535 terms
32
A30
- Abrasive blastingDriving media against a surface with compressed air. The media decides the result far more than the pressure does: angular grit cuts and …
- Abrasive finishingCutting a surface with bonded or loose abrasive — sanding, brushing, lapping, honing, polishing. Each works by replacing the last operati…
- Accessible nameThe string assistive technology announces for an element, computed by the accessible name specification from a fixed precedence: `aria-la…
- AchromaticHaving no hue: black, white, and the greys between, sitting on the central axis of any color solid where chroma is zero. Achromatic work …
- Additive colorMixing by summing emitted light: red, green, and blue primaries combine toward white, and every addition raises luminance. Screens, stage…
- Affine transformAny map preserving straight lines, parallelism, and ratios of lengths along a line, but not necessarily length or angle: translation, rot…
- AlbedoThe fraction of incident light a surface returns by diffuse scattering, per wavelength band — the color light acquires after entering a d…
- AlignmentThe sharing of an edge or an axis by elements not otherwise connected. Alignment creates an implied line the eye follows and structure it…
- AllowanceThe intended difference between mating parts: the tightest condition the limits permit, computed from the largest shaft against the small…
- Alpha ChannelA per-pixel coverage value stored alongside colour, saying how much of the pixel the image occupies — not how see-through its colour is. …
- Alpha CompositingCombining images by coverage. The over operator lays one atop another as c = a + b(1−α), which is associative but not commutative, and it…
- Ambient lightIn a renderer, a constant added to every shaded point regardless of direction, occlusion, or distance — a flat lift with no physical refe…
- Ambient occlusionThe fraction of the hemisphere above a point blocked by nearby geometry — a purely geometric visibility term, no light involved. As a mat…
- AnalogousA scheme of hues adjacent on the wheel, typically spanning thirty to sixty degrees. Adjacency guarantees agreement and withholds tension,…
- AnisotropyRoughness that differs along two tangent directions, stretching the highlight perpendicular to the surface's structure. Produced by anyth…
- Anodized finishThe appearance of an electrochemically grown oxide layer on aluminum: a hard, slightly translucent film with pores that take dye. It conc…
- AnodizingGrowing a controlled oxide layer on aluminium electrolytically. The layer is porous as it forms, takes dye, then gets sealed — so the col…
- Anti-aliasingReconstructing a signal the sample grid cannot represent, by weighting each pixel with the fraction of it a shape covers instead of a har…
- AntumbraThe region beyond the umbra's apex, where the occluder sits entirely inside the source's disc and is ringed by light on every side. It ex…
- APCAA contrast model developed for WCAG 3 that reports a polarity-aware lightness contrast value, Lc, rather than a ratio, and factors in tex…
- ApertureThe opening through which a partly enclosed counter connects to the space around the letter — the gap between the terminals of c and s, t…
- ApexThe junction where two diagonal strokes meet at the top of a letter, as in A and the peaks of M and W. The mirror-image junction at the b…
- Appearance modelA model built to be indistinguishable from the finished product in every visible respect and functional in none. Surfaces, seams, colour …
- Area lightAn emitter with finite extent — rectangle, disc, sphere, or arbitrary mesh — radiating from every point on its surface. Because different…
- ARIAA W3C specification of roles, states, and properties that supply or override accessibility semantics where native markup can't express th…
- ArmA stroke attached at one end and free at the other, projecting horizontally or upward — the three of E, the top of T, the upper stroke of…
- AscenderThe part of a lowercase letter rising above the mean line — b, d, f, h, k, l, and the upper stroke of t. Ascender length is a design vari…
- AsymmetryComposition without correspondence across an axis, balanced instead by trading weight against distance — a small dense element far from c…
- Atmospheric perspectiveDepth read from the air itself: distant forms lose contrast, shift toward the sky's colour, and soften at the edge, because scattering fi…
- AxonometricThe family of parallel projections showing three faces at once, sorted by how many axes share a scale: isometric shares all three, dimetr…
B29
- BalanceThe distribution of visual weight about an axis or a centre so that no part of the field seems to fall. It is judged, not measured. Bilat…
- BandingVisible steps in a gradient that should read as continuous, caused by too few code values across the range being covered — eight-bit enco…
- BaselineThe invisible line on which the flat-bottomed letters of a line of text sit and from which vertical metrics are measured. Round and point…
- Baseline gridAn invisible ruling at a fixed interval to which every baseline in a layout snaps, so text in adjacent columns aligns line for line and h…
- Basic dimensionIn GD&T, an exact theoretical value — boxed on the drawing — that locates or sizes a feature and carries no tolerance of its own. The tol…
- Bead-blasted finishThe uniform, non-directional matte produced by driving media against a surface at pressure, leaving randomly oriented micro-craters. Beca…
- Bevel (modifier)A procedural operation replacing each selected edge with a strip of faces at a set width and segment count — one segment reads as a chamf…
- BézierA polynomial curve defined by control points and evaluated by repeated linear interpolation between them — de Casteljau's algorithm. It p…
- Bezold effectA color's appearance changing when a small amount of a second color is interlaced through it. Unlike simultaneous contrast, which pushes …
- BicameralA script with two cases that pair off — Latin, Greek, Cyrillic, Armenian. The two sets come from different histories: Roman capitals from…
- BlackletterThe dense broken-pen hands of northern Europe and the types cut from them — Textura, Rotunda, Schwabacher, Fraktur. Gutenberg's type was …
- BleedArtwork extended past the trim line so that trim variance never leaves a white sliver at the edge — conventionally 3mm or one-eighth inch…
- BloomA post-process that bleeds luminance outward from the brightest parts of an image, standing in for scattering in the lens, the sensor's c…
- Body fillerPolyester paste mixed with a cream hardener by feel, which cures in minutes and sands like chalk. It fills the dents primer cannot. Spot …
- BokehThe character of the out-of-focus rendering — how a blur circle is filled, whether its edge goes bright or soft, whether it turns to onio…
- BooleanA set operation — union, difference, intersection — between two volumes. It is only well defined on closed, manifold, non-self-intersecti…
- BoringEnlarging an existing hole with a single cutting edge, correcting its diameter and — crucially — its position and straightness. A drill f…
- BoumaThe overall silhouette of a word, named for the vision researcher Herman Bouma. The model that readers recognise words by this shape is d…
- Bounce lightLight redirected off a reflector — card, wall, ceiling, scrim — rather than aimed at the subject directly. The reflector becomes the effe…
- BowlThe curved stroke that encloses a counter — the round of b, p, D and the upper and lower rounds of a double-storey g. In faces with incli…
- BracketThe curved transition joining a serif to the stem it finishes. Heavy bracketing reads as warm and old-style; slight bracketing as transit…
- Brake formingBending sheet metal along a straight line between a punch and a die. The inside radius, not the crease, sets the geometry: material stret…
- BrazingJoining with a filler that melts above roughly 450 °C while the parent metal stays solid throughout. The filler wets both surfaces and ca…
- BreakpointA viewport width at which a layout rule changes. Chosen properly it sits where the content breaks, not where a named device sits: device-…
- BrimA single-layer collar fused to the part's first layer, widening its footprint to resist peeling without lifting the part off the bed. Che…
- Brushed finishThe look of a directional abrasive pass: parallel micro-grooves that stretch the highlight across the lay and make the surface change bri…
- BuckA rigid form that sheet material is shaped over — vacuum-formed, hammered, or laid up against. It carries the outside surface of the part…
- Bump mapA grayscale texture read as height, from which the shader derives a normal perturbation by differencing neighboring texels. Encodes the s…
- Butterfly lightingKey placed high and directly on the camera axis, casting a small symmetrical shadow beneath the nose and a matching one under the chin. I…
C53
- CA glueA one-part adhesive that polymerises on contact with trace surface moisture. Instant, brittle, and gap-intolerant — it wants two surfaces…
- CandelaLuminous intensity: lumens per steradian, light emitted in a given direction. It is the SI base unit for light, defined by fixing the lum…
- Cap heightThe distance from the baseline to the top of a flat-topped capital such as H or E. Round capitals like O and S overshoot it slightly. In …
- Cast shadowThe shape an occluder subtracts from another surface's illumination. Unlike a form shadow it has a projected outline governed by the geom…
- Catmull-ClarkThe subdivision rule for quad-dominant meshes: each face yields a face point, each edge an edge point, and original vertices move toward …
- CausticA concentration of light formed where specular reflection or refraction folds a family of rays onto a diffuse surface — the bright cusp i…
- Cavity mapA texture recording concavity at detail scale — the tight creases, pits, and panel lines, not the form. Usually multiplied into diffuse o…
- ChamferA flat facet cutting across an edge at an angle — typically 45°, and specified as a distance and an angle rather than as a radius. It mee…
- ChatterSelf-excited vibration between tool and work that cuts a regular rippled pattern into the surface, and sounds like it. It is a rigidity p…
- ChiaroscuroThe modelling of volume through strong, unbroken transitions from light to dark, with a small lit passage carrying the subject out of an …
- ChipboardTwo unrelated materials wearing one word. In a wood shop it is coarse resin-bonded particle board: cheap, heavy, it eats cutters and hold…
- ChromaThe strength of a color measured against a neutral grey of the same value — how far it sits from the achromatic axis. Chroma is an absolu…
- Chromatic adaptationThe visual system rescaling its cone responses to the prevailing illuminant, so a white shirt reads white under tungsten and under noon d…
- CIE XYZThe 1931 foundation space: three imaginary primaries derived from color-matching experiments and chosen so that Y carries luminance and e…
- CIELABA device-independent opponent space — L* for lightness, a* green to red, b* blue to yellow — built so equal numeric distances approximate…
- Circle of confusionThe disc a point source projects onto the sensor when it sits away from the focus plane. Depth of field is entirely a decision about how …
- CJKChinese, Japanese and Korean typesetting. Characters occupy a fixed em square, so text sets to an even grid; there are no word spaces, so…
- Clearance fitA fit in which the hole exceeds the shaft across the whole of both tolerance ranges, so the parts always assemble with a gap — guaranteed…
- ClearcoatA second specular lobe layered over the base material to stand in for a transparent coating — car paint, lacquered wood, wet plastic. It …
- Climb cutFeeding so the cutter's rotation runs in the same direction as the feed, taking a thick chip first and thinning it to nothing at exit. Le…
- ClosurePerception completes a figure across gaps, supplying contour that was never drawn. The effect is strongest when the implied shape is simp…
- CMYKThe subtractive process set: cyan, magenta, yellow, and a key black. Black is there because real inks are impure and CMY overprint gives …
- CNC millingMilling driven by a toolpath rather than a hand wheel. Three axes move the tool in X, Y and Z and can only reach what a vertical spindle …
- Color bleedingThe transfer of a surface's chromaticity onto its neighbours by indirect light: the bounce carries the reflector's spectral albedo, so a …
- Color castAn unwanted hue laid uniformly across an image, usually from an illuminant the capture never corrected for or a profile mismatch on outpu…
- Color harmonyThe doctrine that certain hue relations are inherently agreeable, read off fixed angles on a wheel: complementary, analogous, triadic, te…
- Color temperatureThe temperature of a blackbody radiator whose color matches the light in question, given in kelvin. It runs backwards from intuition: 270…
- ColorwayOne specific color combination of a design that exists in several — the same jacket in olive, navy, and rust. The word carries a discipli…
- ColumnA vertical division of the live area, separated from its neighbours by gutters. Column count governs how many measures a page can offer; …
- Common fateElements moving in the same direction at the same rate group together, overriding proximity and similarity for as long as the motion last…
- Common regionElements inside a shared bounded area group together even when proximity and similarity argue otherwise. The boundary can be a rule, a ti…
- ComplementaryA pair of hues opposite one another on a color wheel — but which pair depends entirely on the wheel. In RYB, blue opposes orange; in addi…
- Contact shadowThe tight dark shadow in the crevice where two surfaces meet, produced because almost none of the surrounding hemisphere is visible from …
- ContourA curve of constant height on a surface, read against a fixed direction — the level lines of a topographic map, the ribs of a stacked las…
- ContrastDifference made structural: two elements set far enough apart on some attribute — size, weight, direction, texture, value — that the diff…
- Contrast of complementsDifference between hues that cancel to neutral when mixed. Set adjacent at full chroma they intensify one another to the point of vibrati…
- Contrast of extensionDifference in the area two colors occupy. Itten took Goethe's light values — yellow 9, orange 8, red 6, green 6, blue 4, violet 3 — and i…
- Contrast of hueItten's simplest contrast: difference carried by hue alone, strongest between unmixed primaries. It is also the weakest tool for legibili…
- Contrast of light and darkDifference carried by value. It is the only contrast every viewer receives — colorblind, low-vision, in glare, in greyscale, at a distanc…
- Contrast of saturationDifference between a vivid color and a muted one of similar hue and value. The quietest of Itten's contrasts and the most useful in inter…
- Contrast of temperatureDifference read as warm against cool. It is relative, never absolute: a blue-leaning red is cool beside a scarlet and warm beside any blu…
- Contrast ratio(L1 + 0.05) / (L2 + 0.05), where L is WCAG relative luminance and L1 is the lighter of the two colours. It runs from 1:1 to 21:1. Hue is …
- Control pointOne of the points defining a curve or surface without generally lying on it — the geometry is pulled toward it, not through it. Moving on…
- Conventional cutFeeding against the cutter's rotation, so each chip starts at zero thickness and builds to full. The tool rubs before it bites, which wor…
- Core shadowThe darkest band within a form shadow, lying just past the terminator, where the surface has turned fully away from the key but has not y…
- CounterThe negative space a stroke encloses or partly encloses — fully closed in o, d and the eye of e, open in n, u and c. Counter size drives …
- CreaseA per-edge or per-vertex weight telling a subdivision scheme to pull its limit surface back toward the control mesh, sharpening the resul…
- CropThe decision of what the frame excludes. Cropping changes scale, weight, and reading all at once — a face cut at the crown reads closer t…
- CrossbarA horizontal stroke connecting two stems, as in A and H. Strictly, a stroke that crosses a stem rather than joining two — the horizontals…
- CrownA slight convexity given to a surface that could have been flat — the barely perceptible bulge across a car door, a table top, a rolled p…
- CSGA scheme in which form is a tree of primitives combined by set operations, and the tree — not the resulting surface — is the model. Evalu…
- CSS pixelThe abstract unit CSS lengths resolve to: an angular reference — about 1/96 inch at arm's length, a visual angle near 0.0213° — rather th…
- Curvature mapA texture recording the sign and magnitude of surface curvature per texel: convex edges above mid grey, concave creases below it, flat gr…
D24
- DatumA theoretically exact reference — plane, axis, or point — derived from a real feature and used to orient and locate everything measured f…
- DecimateReducing triangle count by collapsing edges in order of how little each collapse changes the surface, usually by a quadric error metric. …
- Depth cueAny feature of a flat image a viewer reads as depth: overlap, relative size, atmospheric perspective, linear perspective, texture gradien…
- Depth of fieldThe band of subject distances rendering acceptably sharp — where the blur circle stays under a chosen threshold. Exactly one plane is tru…
- DescenderThe part of a letter falling below the baseline — g, j, p, q, y, and in many faces the capital J and Q's tail. Descender depth interacts …
- Design systemThe whole of what a team shares in order to build one thing: tokens, components, patterns, usage guidance, and the process by which those…
- Design tokenA named, single-source value for a design decision — a colour, a step on a spacing scale, a duration — held in a format that transforms i…
- DevanagariThe abugida used for Hindi, Marathi, Nepali and Sanskrit. Letters hang from a headline (shirorekha) rather than sitting on a baseline; vo…
- Developable surfaceA surface with zero Gaussian curvature everywhere, so it unrolls flat without stretching or tearing. The classification is complete and s…
- DidoneThe high-contrast romans of around 1800 — Bodoni, Didot, Walbaum. Exactly vertical stress, abrupt and extreme thick-to-thin, unbracketed …
- DiffractionThe spreading and interference of light as it passes an edge or aperture — a wave effect rather than a ray one. It sets the resolution fl…
- Diffuse mapThe texture supplying a surface's diffuse response. In legacy spec/gloss pipelines it routinely carries baked lighting, ambient occlusion…
- Direct ModelingEditing the boundary geometry itself — grab a face, push it — with no feature tree to replay. Recognition tools infer intent, reading a r…
- Directional lightA source at effectively infinite distance, so its rays arrive parallel and its illuminance does not vary with position. Shadows stay the …
- DispersionThe dependence of refractive index on wavelength, so a single refraction sends each wavelength off at a slightly different angle. It is w…
- Displacement mapA texture whose values move real surface points, normally along the normal, so silhouette, occlusion, and cast shadows all change with it…
- Display P3Apple's display space: DCI-P3's primaries carrying sRGB's D65 white point and transfer curve. Roughly twenty-five percent more volume tha…
- DistressWear applied on purpose — abrasion, chipping, staining, denting — to imitate the appearance of use without the history. It reads convinci…
- DitheringDistributing quantization error across neighbouring pixels so a limited palette approximates colors it does not contain. Ordered ditherin…
- DominanceThe condition of one element carrying more weight than everything else in the field, so the composition has an unambiguous first. Dominan…
- DPIDots of ink per inch that a printing device can place. It describes hardware. A platesetter at 2400 dpi renders a 150-line halftone scree…
- Draft angleThe taper given to a face so a part can leave a mould or a die along the pull direction — measured from that direction, not from the face…
- DuotoneA monochrome image rendered with two inks mapped to different stretches of the tonal range — typically a black holding the shadows and a …
- Dynamic rangeThe ratio between the largest and smallest luminance a scene, sensor, or display can carry, usually quoted in stops of doubling. A real s…
E15
- EarThe small stroke projecting from the upper right of a double-storey g, and by extension the flick at the top of a lowercase r. It carries…
- EdgeThe straight segment between two vertices, and the unit that carries a mesh's structure. How many faces share an edge classifies it: exac…
- Edge loopA path of edges that continues straight through every four-valence vertex it meets, turning neither left nor right, and usually closing o…
- Edge ringThe set of edges lying across a loop rather than along it — each is the opposite edge of the next quad in a chain, so a ring and a loop r…
- Edge SeamA seam in the model itself: a line where the surface is split so normals do not average across it, giving a hard shading break, or where …
- Elephant's footThe bulge at a print's base where the first layers, pressed into the bed and still soft under the weight above, spread wider than the mod…
- EmA relative unit equal to the current type size: at 16px, one em is 16px. It is not the width of an M and never was a measurement of any g…
- EmissiveRadiance a surface produces on its own, independent of anything illuminating it — a screen, an LED, hot metal. In most real-time pipeline…
- EmphasisThe deliberate raising of one element above the field — by contrast, isolation, scale, placement, or the direction of the forms around it…
- EnHalf an em. Its practical residue is the dash: the en dash spans ranges and compound relations (1914–18, the Paris–Lyon line), the em das…
- Energy conservationThe constraint that a surface cannot return more light than it receives. Diffuse and specular responses draw on one budget, so a brighter…
- EpoxyA resin and a hardener that co-react rather than dry, so it cures inside a gap and will fill one. Strong on nearly everything, slow, and …
- ExposureStrictly, the illuminance on the sensor multiplied by the time it is collected — lux-seconds, set by aperture and shutter alone. It deter…
- ExtrudeSweeping a profile along a straight path, generating surface behind it. A closed profile extruded gives a prism — the operation that make…
- Eye pathThe sequence in which a viewer's fixations land on a composition, driven by weight, alignment, continuation, and habit. The entry point i…
F19
- FaceA region bounded by a closed loop of edges — the smallest unit a renderer shades. Its vertices are assumed coplanar; three always are, fo…
- Faux small capsCapitals scaled down to approximate x-height. Scaling reduces stroke weight along with height, so they sit lighter and narrower than the …
- FBXA scene format carrying meshes, hierarchies, materials, cameras, lights, skinning, and animation — the industry's working interchange for…
- FDMExtruding molten thermoplastic in stacked paths. Cheap, forgiving, dimensionally decent. But the part is a stack of welded beads: strong …
- Feed and speedThe pair that governs every rotating cut: how fast the tool turns and how fast it advances. Together they set chip thickness. Too slow a …
- Figure–groundThe partition of a field into a form that has shape and a ground that runs behind it. The figure owns the shared contour; the ground does…
- Fill lightA secondary source that raises illuminance on the shadow side, controlling how much detail survives there. Fill sets the lighting ratio r…
- FilletA rounded transition replacing a sharp edge, generated by rolling a circle of fixed or varying radius into the corner and trimming both f…
- First-angle projectionThe multiview arrangement in which the object sits between the viewer and the plane, so each view is projected through it and lands on th…
- Fit classA standardised pairing of hole and shaft tolerance zones — H7/g6, RC4 — producing a known relationship without designing limits from firs…
- FixtureA device that locates and clamps work in a repeatable position and does not guide the tool. Every CNC operation needs one; its whole job …
- FlashMaterial that squeezed into the gap between mould halves and cured there — a thin fin standing proud of the parting line. It reports clam…
- Fluid scaleSizing that interpolates continuously between a minimum and a maximum across a viewport range — typically CSS `clamp()` with a viewport-u…
- Focus indicatorThe visible marker showing which control holds keyboard focus. WCAG 2.0 SC 2.4.7 (AA) requires only that some mode of focus is visible. W…
- FontThe thing that renders a typeface — historically one size and one style of metal sorts in a case, now a file: Garamond Italic 10pt was a …
- ForeshorteningThe compression of a form's apparent length as it turns away from the picture plane — the same projection that produces convergence, appl…
- Form shadowThe region of an object turned away from the light — unlit because of its own orientation, not because anything blocks the source. Its bo…
- FramingElements inside a composition that enclose another and route attention to it — an arch, a doorway, a bank of shadow, a column of text. A …
- FresnelThe angle- and wavelength-dependent split of light at a boundary between reflected and transmitted. Reflectance is at its minimum facing …
G27
- G1 continuityTwo curves or surfaces meet G1 when they share a point and a tangent direction there, but not necessarily curvature. The join reads as sm…
- G2 continuityTwo curves or surfaces meet G2 when they share position, tangent, and curvature at the join — the curvature comb crosses it without a ste…
- GammaThe power-law transfer function between encoded code values and light — historically the CRT's own response near 2.2, now kept deliberate…
- GamutThe set of colors a device or space can actually produce — a volume rather than an area, since reach changes with lightness. Every gamut …
- GaraldeThe dominant text roman from roughly 1500 to 1750 — Bembo, Garamond, Granjon, Caslon. Compared to the humanists: more stroke contrast, a …
- GateThe restricted opening where material finally enters the cavity, deliberately smaller than the sprue feeding it. The restriction speeds a…
- Gaussian curvatureThe product of the two principal curvatures at a point, K = κ₁κ₂. Positive on a dome where both bend the same way, negative on a saddle w…
- GD&TA symbolic language — ASME Y14.5, or ISO's GPS standards — for tolerancing a part by function rather than by coordinate. Controls for for…
- Generative DesignAn optimizer proposes geometry against stated goals and constraints — loads, keep-outs, mass, manufacturing method — and returns candidat…
- GenusThe number of handles on a closed orientable surface — holes you could thread a string through, not dents or openings. A sphere is genus …
- Geometric sansSans serifs built from circle, square and triangle — Futura, Erbar, Kabel, and their descendants. Near-monoline, single-storey a, circula…
- GestaltThe body of perceptual regularities described by Wertheimer, Köhler, and Koffka from 1912 onward, holding that perception organizes a fie…
- Gimbal lockThe loss of one rotational degree of freedom when two axes of a three-angle Euler rotation align: at 90° of pitch, yaw and roll turn abou…
- GlareVisual impairment or discomfort caused by a luminance in the field of view far above what the eye is adapted to. Disability glare measura…
- Global illuminationAny solution to light transport accounting for light that arrives after reflecting off other surfaces, not only direct from emitters. It …
- GlossThe degree to which a surface reflects specularly rather than diffusely — and, unusually for this vocabulary, an actually measured quanti…
- GlossinessThe inverse parameterization of roughness: the same microfacet distribution addressed from the smooth end. High glossiness means a narrow…
- glTFAn open delivery format for runtime 3D: meshes, PBR materials, skins, animation, and a scene graph, held in JSON with binary buffers laid…
- Golden ratioThe ratio 1:1.618…, in which the whole stands to the larger part as the larger part stands to the smaller. A rectangle carrying it subdiv…
- Good continuationElements arranged along a continuous line or smooth curve read as belonging to one another, and the path preferred is the one that change…
- GradationChange applied by a rule across a sequence — size, value, spacing, or weight stepping in a consistent progression. Gradation gives direct…
- GradientA continuous interpolation between two or more colors across a region, evaluated per pixel. What it looks like depends entirely on the sp…
- GrainThe directional structure a material carries from how it was made — fibers aligned in wood and paper, silver halide in film, the rolling …
- GridA structure of repeated divisions — columns, rows, gutters, margins — fixing where elements may start and stop. Its value is decisional r…
- Grit progressionWorking through abrasives in sequence so each grade removes only the scratches the previous one left. Skipping a step leaves deep scratch…
- GrotesqueThe nineteenth-century sans serifs — Akzidenz-Grotesk, Franklin Gothic, News Gothic. Slight irregularity between letters, a squarish rath…
- GutterThe space between two columns or two modules. It must be wide enough that the eye does not carry a line across it into the neighbour, and…
H18
- H&JThe rule set governing how lines break and fill: minimum, optimum and maximum word spacing, permitted letter spacing and glyph scaling, h…
- HairlineThe thinnest stroke in a letter, and the denominator of stroke contrast. Didones drive the ratio past 10:1; humanist faces keep it near 2…
- HalationA halo around a bright area caused by light passing through the recording layer, reflecting off whatever sits behind it, and re-exposing …
- HalftoneContinuous tone simulated by dots of varying size on a fixed grid, because a press can lay ink or not lay ink and nothing in between. App…
- HarmonyAgreement among parts that differ — elements drawn from a common family, related by shared proportion, angle, or interval, so they read a…
- HazeWide-angle scatter in a material that still transmits an image: the image comes through, but a milky veil sits over it and the blacks beh…
- HDRAs imaging, storing luminance in floating point so nothing clips. As a display standard, a higher peak luminance, a perceptual transfer f…
- HDRIA photographic capture of the whole sphere of incident radiance at a point, stored in floating point so the sun stays thousands of times …
- Helmholtz–Kohlrausch effectSaturated colors looking lighter than their measured luminance says they should, the gap widening with chroma and largest around blue and…
- HierarchyThe ordering of a composition's parts by intended attention, expressed through weight, scale, position, and space. A hierarchy is a claim…
- High keyA tonal strategy placing most of a scene's values in the upper register with a low key-to-fill ratio, so shadows stay open and transition…
- HintingInstructions embedded in a font telling the rasteriser how to distort outlines onto a coarse pixel grid — snap stems to whole pixels, hol…
- Horizon lineThe line at the viewer's eye height on the picture plane, holding the vanishing points of every set of horizontal parallels. It is set by…
- HSBRGB remapped to hue, saturation, and brightness, where B 100% is the brightest the display can render that hue — so pure yellow and pure …
- HSLA cylindrical remapping of RGB into hue, saturation, and lightness, with L running 0 to 100% and every fully saturated hue landing at L 5…
- HueThe attribute by which a color is identified as red, yellow, green, blue, or a point between — its position around the circle, set by dom…
- Humanist sansSans serifs drawn on the proportions of the humanist roman rather than on geometry — Gill Sans, Frutiger, Myriad, Source Sans. Varied let…
- Humanist serifThe first roman types, cut in Venice from the 1470s and revived since — Jenson, Centaur, Adobe Jenson. Marked by low stroke contrast, str…
I15
- IES profileMeasured photometric data for a real fixture, tabulating luminous intensity in candela across a grid of angles. A renderer reads it to re…
- IlluminanceLuminous flux arriving per unit area, measured in lux — the photometric counterpart of irradiance. It describes light falling onto a surf…
- Index of refractionThe ratio of light's speed in vacuum to its speed in a medium, setting both how far a ray bends on entry, per Snell's law, and how much r…
- Indirect lightLight reaching a point only after one or more reflections off other surfaces. It carries their colour, arrives from broad directions rath…
- InfillThe sparse internal lattice printed inside a hollow shell, set as a percentage. Beyond roughly 40% it buys almost no strength — stiffness…
- InflectionThe point where a curve's curvature passes through zero and changes sign — where the bend reverses from one side of the curve to the othe…
- Ink trapA notch cut out of a join — where shoulder meets stem, or at a tight crotch — so that ink spreading on absorbent paper fills it rather th…
- Interference fitA specified fit where the shaft exceeds the hole across the whole of both tolerance ranges, so the two must be forced, heated or chilled …
- InterpolationGenerating intermediate values between known ones — points along a curve, frames between keys, a surface between defining sections. Linea…
- Inverse-square lawIlluminance from a point source falls as one over distance squared, because the same flux spreads across a sphere whose area grows with t…
- Investment castingA wax original is invested in ceramic slurry, the wax burned out, and metal poured into the void it left. The mould is destroyed to relea…
- IridescenceColor that shifts with viewing angle, produced by thin-film interference: light reflecting off the top and bottom faces of a film only a …
- IrradiancePower arriving per unit area of a surface, in watts per square metre — the cosine-weighted integral of incoming radiance over the hemisph…
- IsometricThe axonometric case in which all three axes meet the picture plane at equal angles — drawn at 30° from horizontal — so all three take th…
- ItalicA separately drawn companion to a roman, based on a cursive hand: narrower, with different letter structures — a single-storey a, an f wi…
J3
- JigA device that holds work and guides the tool — a drill jig has hardened bushings that put the bit exactly where it belongs, every time, w…
- JustificationSetting text flush to both margins by varying the space within each line — chiefly word spacing, with letter spacing and glyph scaling as…
- JuxtapositionThe placing of two elements adjacent so that each is read through the other. The meaning arises in the gap rather than in either part — t…
K4
- KelvinThe temperature of the blackbody whose emission a source's colour most nearly matches — 1,900 K for candlelight, 5,500 for midday sun, 6,…
- KerfThe width of material a cutting tool destroys as it passes — the slot itself, not the line it was drawn on. A blade, laser, or waterjet h…
- KerningAdjusting the space between one specific pair of glyphs, correcting fits the sidebearings can't get right on their own — AV, To, r. — bec…
- Key lightThe dominant source in a setup — the one that establishes the direction of the light, the placement of the form shadow, and the exposure …
L24
- LabelThe visible text naming a control, and in HTML the `label` element that binds that text to an input — so clicking it focuses the field an…
- LacquerA finish that hardens by solvent evaporation alone, with no chemical cure. Each coat partly redissolves the one beneath, so the film buil…
- Lap jointTwo members overlapping, each usually recessed by half its thickness so the faces finish flush. Fast to cut, generous in glue area, and h…
- Laser cuttingBurning through sheet with a focused beam. The cut is a taper, not a slot — the top edge is wider than the bottom — and every edge is hea…
- Layer heightThe Z increment between deposited or cured slices. It sets stair-stepping on sloped surfaces and print time in direct inverse proportion,…
- LeadingThe vertical distance from one baseline to the next. It is set against measure, not in isolation: a long line needs more of it for the ey…
- LegibilityHow easily individual characters are told apart — a property of the typeface. It is measurable: aperture, x-height, stroke contrast, and …
- Lens flareArtifacts from light reflecting between the elements of a lens instead of passing through — ghosts of the aperture marching across the fr…
- Level AAThe middle WCAG conformance level, and the one policy nearly always specifies. Requires every Level A and Level AA criterion: text contra…
- Level AAAThe highest WCAG conformance level: text contrast 7:1, or 4.5:1 for large text, alongside criteria such as enhanced target size at 44×44 …
- LigatureOne glyph replacing a sequence, applied by OpenType's GSUB table. Standard ligatures (liga) fix collisions the letters make on their own …
- Light probeA sample of the incident light at a chosen point, stored so shading elsewhere can look it up instead of tracing rays. An irradiance probe…
- Line conventionsThe graded weights and dash patterns that carry meaning on a drawing: thick continuous for visible edges, dashed for hidden ones, chain-d…
- Linear perspectiveA geometric construction projecting a three-dimensional scene onto the picture plane from one fixed eye point, so that parallel lines con…
- Lining figuresNumerals of uniform height, aligned on the baseline and reaching to cap height or a little below. The default in most faces since the nin…
- Local spaceThe coordinate frame an object's vertices are actually stored in: origin at the object's pivot, axes fixed to the object. Vertex data doe…
- LODA set of alternative representations of one asset at decreasing complexity, swapped by screen coverage or distance so the renderer spends…
- LoftBuilding a surface through a series of profile curves placed along a form — the skin passes through each section rather than dragging one…
- Loop lightingKey about thirty to forty-five degrees off axis and a little above eye level, producing a small nose shadow that loops down toward the co…
- Low keyA tonal strategy in which most of the frame sits in the lower register and a small, controlled area carries the light. The ratio is high,…
- LumenThe unit of luminous flux: total light power emitted in every direction, weighted by the eye's response. It says how much light a source …
- LuminanceRadiance weighted by the eye's photopic sensitivity and integrated over wavelength — candela per square metre. It measures light leaving …
- LusterThe character of a surface's reflected light rather than its quantity. Mineralogy names the kinds — vitreous, metallic, waxy, resinous, g…
- LuxOne lumen per square metre — the unit of illuminance. Overcast daylight runs around 1,000 lux, an office 300 to 500, full sun past 100,00…
M24
- ManifoldA surface on which every point has a neighbourhood that looks like a flat disc. For a mesh this reduces to two rules: every edge is share…
- MarginThe unmarked band between the live area and the trim. Margins are not leftover: they hold the block in place optically, absorb trim varia…
- MaskA grayscale image that restricts where an operation applies — a per-pixel weight on an effect, not part of any image's own colour. Numeri…
- MassThe perceived weight and presence of a form — how convincingly it reads as being made of something. It is a judgement, not a measurement:…
- MasterThe finished original a mould is taken from when the goal is copies of that exact object — usually the appearance model itself, surfaced …
- Material honestyThe position that a material should present as itself rather than impersonate another: plastic reading as plastic, not as wood grain. A m…
- MatteA surface that returns light almost entirely by diffuse scattering, so no image of the environment survives and brightness holds roughly …
- MDFWood fibre and resin pressed into a homogeneous panel with no grain and no voids, which is why it machines to a crisp edge in any directi…
- Mean curvatureThe average of the two principal curvatures, H = (κ₁ + κ₂) / 2. Unlike Gaussian curvature it depends on how the surface sits in space rat…
- Mean lineThe line touching the tops of the flat lowercase letters — x, v, z — with round letters like o and e overshooting it. The distance from t…
- MeasureThe horizontal length of a line of text, historically in picas and now most honestly in characters. Somewhere around 45–75 characters is …
- MetalnessA switch selecting which reflectance model a surface obeys. Conductors have effectively no diffuse response and tint their specular refle…
- MetamerismTwo samples with different spectral curves matching under one illuminant and separating under another. The match was never in the samples…
- MicrofacetThe modeling assumption that a surface too small to resolve is a field of perfect mirrors, described statistically by a normal distributi…
- MillingCutting with a rotating multi-flute tool while the work moves against it, producing planes, pockets, and profiles. The side of the cutter…
- MockupA stand-in built to answer one question — does it fit, does it read, is it the right size — with no obligation to work or to be made of t…
- Modular scaleA set of sizes generated by multiplying a base repeatedly by a fixed ratio — 16 at 1.25 gives 20, 25, 31.25 — so every step relates to ev…
- ModuleOne unit of a grid divided on both axes — a rectangle bounded by gutters, occupied alone or combined with its neighbours. Müller-Brockman…
- MoldThe negative that gives cast or formed material its shape. One-part block moulds suit simple forms with a flat back; two-part moulds spli…
- Mold makingThe practice of making the negative: choosing where the parting line falls, deciding how many parts the mould needs, matching a rubber or…
- Mold releaseA sacrificial barrier film between mould and casting so the two separate. Wax, PVA and silicone sprays each fail differently: wax builds …
- MonochromaticA scheme built from one hue, varied only in value and chroma. It cannot fail on harmony, since there is no second hue to disagree with, a…
- Mortise and tenonA projecting tongue on one member seated in a matching hole in the other, resisting racking in every direction and offering long-grain gl…
- Munsell systemAlbert Munsell's 1905 ordering of color by hue, value, and chroma, notated as 5R 4/14. The achievement was perceptual spacing settled by …
N14
- N-gonA face with five or more vertices. Legal geometry, but its interior triangulation is decided by whichever program touched it last and may…
- NapRaised fiber ends standing off a textile or paper and lying in one direction, so the surface reflects and feels different with the lay an…
- NCSThe Swedish standard, built on Hering's opponent theory rather than on measurement: a color is described by how much it resembles the six…
- Negative spaceThe unoccupied area of a composition — unoccupied only in the sense that nothing was placed there. It carries shape, groups and separates…
- Neo-grotesqueThe 1950s rationalisation of the grotesque — Helvetica, Univers, Folio. Irregularities planed off, terminals cut horizontally, apertures …
- NitThe working name for candela per square metre, the unit of luminance. A phone in a dim room sits near 100 nits, a laptop outdoors pushes …
- Nominal dimensionThe round-number size a feature is called by — 2×4 lumber, half-inch pipe, an M6 bolt. It names a class of part and is frequently not the…
- Non-destructive EditingKeeping edits as a re-evaluable stack over untouched source data rather than writing results back into it. Adjustment layers, smart objec…
- Non-text contrastWCAG 2.1 SC 1.4.11, Level AA: user interface components, their states, and the parts of graphics needed to understand content must reach …
- NormalThe unit vector perpendicular to a surface at a point, fixing which side is outward. A face normal follows from the winding order of its …
- Normal BakingRecording a high-resolution surface's normal direction per texel into a map the low-resolution mesh reads, so a flat face shades as if th…
- Normal mapA texture encoding a perturbed shading normal per texel, XYZ packed into RGB, usually in tangent space so it survives deformation. It cha…
- NURBSA curve or surface defined by control points, a degree, a knot vector, and a weight per point. Non-uniform knots allow unequal spans and …
- NURBS ModelingBuilding form as a patchwork of mathematically exact rational spline surfaces, each a grid of control points with a degree and a knot vec…
O15
- OBJA plain-text mesh format carrying vertices, faces of any size, UVs, normals, and material references in a sidecar .mtl file. No animation…
- ObliqueA slanted version of the roman with its letter structures intact — Helvetica Oblique, and every sans that calls its slant an italic. A dr…
- OKLabBjörn Ottosson's 2020 revision of the Lab approach, fitted to modern appearance data. It corrects CIELAB's blue-hue skew and its weak lig…
- OKLChOKLab in cylindrical coordinates — lightness, chroma, hue angle. The arrangement designers actually want: hold L and sweep H and the swat…
- Oldstyle figuresNumerals with ascenders and descenders — 6 and 8 rise, 3, 4, 5, 7 and 9 drop, the rest sit at x-height. They carry the same rhythm as low…
- OpacityHow much a surface blocks light passing through it, stored per texel or set per material. A compositing quantity rather than a physical o…
- OpenTypeThe font format in universal use since the late 1990s, holding either TrueType or PostScript/CFF outlines in one file, Unicode-mapped, cr…
- Optical centerThe point a viewer takes for the centre of a field, which sits above the geometric centre — conventionally by around five percent of the …
- Optical sizeA design adjusted for the size it will be set at: at small sizes, open apertures, lower contrast, looser fitting, sturdier hairlines; at …
- Optical spacingFitting letters so the white between them looks even rather than measures even — a straight-sided n takes more space beside it than a rou…
- ORM packingStoring occlusion, roughness, and metalness in the R, G, and B channels of one texture, since each is a single-channel grayscale quantity…
- OrphanA paragraph's opening line left alone at the foot of a column or page while the rest of the paragraph moves on. It reads as a false start…
- Orthographic projectionProjection along parallel lines perpendicular to the picture plane, so faces parallel to that plane record true size and shape with no pe…
- OverlapOne form covering part of another, which fixes their depth order absolutely: the occluder is nearer, and no other cue can overrule it. Th…
- OvershootThe small amount by which round and pointed letters extend past the baseline, mean line or cap line so that they appear the same size as …
P40
- Page canonA ruler-and-compass construction deriving text-block position and margin proportion from the page's own proportions, using diagonals draw…
- Parametric ModelingA model recorded as an ordered sequence of operations bound to editable parameters and to references on earlier geometry. Change a dimens…
- Parting lineWhere the halves of a mould meet, printed onto every part that comes out of it as a faint raised seam. It exists whether or not anyone de…
- Partitive mixingMixing that happens in the eye rather than in the medium: marks too small to resolve individually average into one percept, weighted by t…
- Past experienceGrouping shaped by what the viewer has seen before rather than by the stimulus itself: a shape parses as a letter, a floor plan, a face b…
- PathThe drawing primitive of vector graphics: an ordered sequence of line and curve segments, open or closed, carrying a fill rule and a stro…
- Path tracingMonte Carlo integration of the rendering equation: follow a random walk from the camera, sampling one scattering direction per bounce, an…
- PatinaA stable layer formed by a material reacting with its environment over time — carbonate on bronze, oxide on weathering steel, oil and wea…
- PatternThe object a mould is made from. It carries every surface the casting will have, plus the allowances the casting will not: draft so it re…
- PearlescenceThe soft, layered glow of many thin platelets — mica, nacre, coated flakes — suspended at varied depths beneath a translucent surface, ea…
- PenumbraThe graded margin of a shadow from which part of the source is visible and part is blocked. Its width grows with the source's angular siz…
- PhotogrammetryReconstructing geometry from overlapping photographs by matching features across views, solving for camera positions, and triangulating a…
- PicaTwelve points, and under the PostScript convention a sixth of an inch — six picas to the inch, seventy-two points. The unit column widths…
- Picture planeThe flat surface an image is constructed on — in perspective theory, the transparent plane the scene is projected onto, standing between …
- PlatingDepositing metal onto a conductive part from solution, electrically or by autocatalytic reaction. The deposit follows the substrate exact…
- Platonic solidOne of exactly five convex polyhedra whose faces are congruent regular polygons meeting identically at every vertex: tetrahedron, cube, o…
- PMMAA hard, optically clear thermoplastic that laser-cuts to a flame-polished edge and solvent-welds invisibly. Cast acrylic machines and las…
- PointThe unit of type size, standardised as exactly 1/72 inch by PostScript and every application since. Historically it was never one thing: …
- Point CloudAn unstructured set of measured 3D points, often with colour and estimated normals, and with no connectivity: no edges, no faces, no surf…
- Point lightAn idealized source of zero extent radiating equally in all directions from a single position. Because it has no size it subtends no soli…
- PoleA vertex where a number of edges other than four meet — three-valence (E-pole) and five-valence (N-pole) being the common cases. Poles te…
- Polished finishAn abrasive progression taken until the remaining scratches are shorter than a wavelength of visible light, at which point the surface re…
- Polygonal ModelingBuilding form from an explicit mesh of vertices, edges, and faces, moved and cut by hand. The mesh is the final surface, so its resolutio…
- PosterizationReduction of a continuous tonal range to a small number of flat steps, named after the flat-inked poster it imitates. As an effect it is …
- POURThe four principles WCAG's success criteria are organised beneath: perceivable, operable, understandable, robust. A filing system rather …
- Powder coatingElectrostatically spraying dry pigmented polymer onto a grounded part, then flowing it out in an oven. The film is thick — 60 to 100 micr…
- Powder-coat finishThe appearance of an electrostatically applied polymer fused by heat into a film: thick, fully opaque, soft at the edges, and available i…
- PPIImage samples per inch at a stated reproduction size, or the physical pixel pitch of a display. It describes a relationship between a fil…
- PracticalA fixture that appears in frame and is actually lit — a lamp, a screen, a candle. It motivates the light the audience is asked to believe…
- PrägnanzThe overarching gestalt claim: of the readings a stimulus permits, perception settles on the simplest, most regular, most stable one. 'Si…
- Press fitA joint held by friction alone between deliberately mismatched sizes, assembled by hand or arbor press. In a model shop it is how printed…
- PrimerA coating formulated to stick to the substrate, be stuck to, and sand. It is neither paint nor filler: high-build primer fills tool marks…
- PrimitiveA parametric solid supplied ready-made by a modeling application — box, sphere, cylinder, cone, plane, torus — described by a handful of …
- Print anisotropyA printed part is not one material — it is stacked welds. FDM strength across layers runs roughly half that along them, and the fracture …
- Procedural ModelingGenerating geometry from rules — a graph, a script, a grammar — rather than placing it. The output is a function of its inputs, so changi…
- ProfileThe shape of a form's cross-section along its defining direction, or the curve that generates it — the section a sweep drags, the shape a…
- ProportionThe relation of one dimension to another — within an element, between elements, or between an element and the whole. Proportion is a rati…
- PrototypeStrictly, the first article made to test whether a design works. The word has been diluted until it means any model at all, including ren…
- ProximityElements near one another read as a group before any other cue is weighed. Distance does the work, and it is relative: a field is parsed …
- Purkinje shiftAs light falls and vision hands over from cones to rods, peak sensitivity moves from about 555 nm to 505 nm. Reds darken toward black and…
Q1
R34
- RadiancePower per unit projected area per unit solid angle — the quantity carried along a single ray. It is constant along that ray in a vacuum, …
- RadiosityStrictly, a finite-element method that divides a scene into patches, computes form factors between them, and solves the resulting linear …
- Radius breakThe line where a fillet stops and the flatter surface it blends into begins — the tangent boundary of the round. A highlight terminates t…
- RaftA disposable slab printed under the whole part to isolate it from the bed, giving warp-prone material a flat surface of its own to build …
- RagThe uneven edge of unjustified text. A good rag is worked, not accepted: it varies line to line without falling into a wedge, a staircase…
- RasterAn image stored as a grid of samples. It has no notion of what it depicts — a letterform in a raster is not a letter, it is the pixels a …
- RasterizationTurning geometry into pixels by projecting each triangle to screen space and filling the pixels it covers, with visibility settled by a d…
- Ray tracingHistorically, Whitted's 1980 method: trace one ray per pixel, recurse into the mirror and refraction directions, and fire shadow rays at …
- ReadabilityHow easily a reader gets through extended text — a property of the setting and the writing, not the face. Measure, leading, contrast, ali…
- ReamingFinishing a drilled or bored hole with a multi-fluted tool that removes only a few thousandths, producing a precise diameter and a smooth…
- Rec. 2020The ITU's ultra-high-definition space, with primaries sitting on the spectral locus itself. No real display reaches them, and that is del…
- Recto and versoThe two sides of a leaf: recto the right-hand page, verso the left. The pair, not the page, is the unit a reader actually meets — nobody …
- ReflectionThe isometry mapping each point to its mirror image across a plane, or across a line in 2D. It reverses handedness and winding order, so …
- ReflowWCAG 2.1 SC 1.4.10, Level AA: content must present without loss of information or functionality, and without scrolling in two dimensions,…
- RefractionThe bending of light as it crosses between media of differing index, because its phase velocity changes; Snell's law fixes the new angle …
- Relative luminanceThe quantity WCAG contrast is computed from: sRGB channels linearised through the transfer function, then weighted 0.2126 R + 0.7152 G + …
- RemA CSS length equal to the computed font size of the root element — 16px by default, and whatever the reader has set otherwise. Unlike em …
- Rembrandt lightingA portrait pattern in which the key sits high and roughly forty-five degrees off axis, so the nose shadow meets the cheek shadow and stra…
- RemeshReplacing a mesh's topology wholesale with a new, evenly distributed one approximating the same surface. Voxel remeshers rasterize to a g…
- RepetitionThe reuse of an element across a composition or a body of work. Repetition builds unity and lets a reader stop re-decoding what they have…
- ResinA dangerously ambiguous word. It names polyurethane casting resin, polyester laminating resin, epoxy, and photopolymer for SLA printers —…
- ResolutionAmbiguous by use. The word names pixel dimensions (4096 by 4096), sampling density (300 ppi), and sometimes an output size in inches — th…
- RetopologyBuilding a new, deliberately laid-out mesh over an existing surface, by hand or with guided automation. The goal is not fewer polygons; i…
- RetroreflectionReflection that returns light toward its source across a wide range of incidence angles, achieved with corner-cube prisms or embedded gla…
- RGBAn additive model addressing color as amounts of red, green, and blue primaries. RGB by itself specifies nothing absolute: the same tripl…
- RhythmRecurrence at intervals the eye can feel. Regular rhythm repeats one interval, alternating rhythm swaps between two, progressive rhythm c…
- Right-to-leftScripts written right to left — Arabic, Hebrew, Persian, Urdu. Text is stored in logical order and reordered for display by the Unicode b…
- Rim lightA source behind the subject, aimed back toward the camera, that grazes the contour and separates it from the background. It reads as a br…
- RiserA reservoir attached to a casting that stays molten longer than the part and feeds metal back in as the part shrinks while it freezes. Wi…
- RiverA channel of white running down or diagonally through a text block where word spaces on consecutive lines happen to align. A justified-se…
- Rotational symmetryInvariance under rotation about an axis by 360°/n for some integer n, called the order of the symmetry. Order 2 is a half-turn. A shape w…
- RoughnessThe statistical spread of microfacet normals across a surface, controlling how tightly reflected light clusters around the mirror directi…
- RTV siliconeTwo-part rubber that cures at room temperature into a flexible mould. Tin-cure is cheap and forgiving, shrinks slightly, and slowly dies …
- Rule of thirdsA convention placing the frame's divisions at one-third and two-thirds on each axis and subjects near the four intersections. It is a coa…
S66
- Sand castingPacking bonded sand around a pattern, withdrawing the pattern, and pouring metal into the cavity it leaves. The mould is broken up afterw…
- SatinThe middle of the gloss ladder: enough specular return to catch a soft highlight, too much scatter to reflect a legible image. The paint …
- SaturationChroma judged relative to the color's own brightness — how vivid it appears given how light it is. Being a ratio rather than a distance, …
- ScaleThe size of a thing relative to a reference — the frame, the body, another element, or the real-world object depicted. Scale is a relatio…
- ScaleMultiplying coordinates by a factor about a fixed point. Uniform scale preserves angles and shape; non-uniform scale does not, and it dis…
- ScatteringLight redirected out of its path by particles or inhomogeneities rather than by a smooth boundary. Rayleigh scatter, off things far small…
- Screen readerSoftware that renders an interface as speech or braille from the accessibility tree — the platform's parsed model of roles, names, and st…
- ScriptFaces modelled on handwriting, whether formal copperplate (Snell Roundhand), casual brush, or blackletter-adjacent hands. Connecting scri…
- SculptingPushing a very dense surface with brushes rather than editing vertices one at a time — the mesh is a medium, not a structure. Detail is b…
- SDFForm defined as a function returning the distance from any point to the nearest surface — negative inside, positive outside. The surface …
- SectionThe figure produced by cutting a form with a plane and looking squarely at the cut face — only what the plane intersects, hatched, with n…
- Semantic markupUsing elements for what they mean rather than how they look — a button as `button`, a heading as `h2` — so role, state, and keyboard beha…
- Semantic tokenA token named for its role rather than its value — `color.text.subtle`, not `gray.600` — pointing at a primitive token beneath it. The pr…
- SerifThe finishing stroke crossing or projecting from the end of a main stroke. Serifs vary along two axes that matter: bracketed or unbracket…
- ShadeA hue with black added — darker and lower in chroma than the parent. Black is a blunt instrument: it kills chroma quickly and drags most …
- ShaderA program run per vertex or per fragment that returns a value — usually a colour, sometimes a position, a depth, or an arbitrary buffer. …
- Shadow softnessHow wide a shadow's penumbra is, governed by one quantity: the angular size the source subtends from the point in shadow. A source is har…
- SheenAn extra grazing-angle lobe layered over the base response to approximate the soft bloom of fabric, where light catches the protruding en…
- Sheet metalMetal supplied as flat stock and worked cold — cut, bent, punched, rolled. Because the material will not stretch far, the achievable form…
- ShellThe solid outer walls of a print, counted in perimeters rather than measured in millimetres. Shells carry the load, close the surface, an…
- Short lightingA pair of opposites describing where the key falls relative to the camera on a turned head. Short lighting puts the lit side away from th…
- ShoulderThe curved stroke that springs from a stem and comes back down without closing — the arches of h, m, n and the underside of u inverted. W…
- Shrinkage allowanceExtra size built into a pattern because the casting contracts as it cools or cures. Aluminium runs about 1.3%; urethane resin a few tenth…
- SidebearingThe space built into a glyph on either side of its outline. Left sidebearing plus the outline's width plus right sidebearing gives the ad…
- SilhouetteThe outline a form presents from a given viewpoint — the boundary between surfaces facing the viewer and those facing away. It is view-de…
- SimilarityElements sharing a visual attribute — shape, size, value, hue, orientation, texture — group across distance. The grouping strengthens wit…
- Simultaneous contrastA color's appearance shifting according to what surrounds it: a grey patch on red takes a greenish cast, the same grey on green turns fai…
- SLACuring liquid photopolymer layer by layer with light. Resolution is set by optics rather than a nozzle, so fine detail and smooth walls c…
- Slab serifFaces whose serifs are heavy rectangles roughly the weight of the stems, with contrast near nil. Two branches that behave differently: br…
- SlicingTurning a closed solid into the machine's actual instructions: intersecting the mesh with a stack of planes to get contours, filling each…
- SLSFusing nylon powder in a heated bed layer by layer, with the unfused powder supporting the part. No support structures at all, so geometr…
- Small capsCapitals drawn at roughly x-height, redrawn rather than reduced: proportionally wider, with stems thickened to match the lowercase's colo…
- SmoothingTwo different things under one word. Mesh smoothing — relax — moves vertices toward the average of their neighbours, evening out spacing …
- SolderingJoining with a filler melting below roughly 450 °C, wetting surfaces that flux has cleaned. The result is a mechanical and electrical con…
- Solid ModelingRepresenting a part as a closed watertight volume: trimmed faces stitched along shared edges, with an inside and an outside the kernel ca…
- Solvent weldNot glue. The solvent dissolves both faces and they fuse into one piece of plastic as it flashes off. Works only where a solvent for the …
- Spacing scaleThe restricted set of gap values a system permits — usually a base unit stepped geometrically or in multiples of four or eight — applied …
- SpecularIn metal/rough conventions, a scalar remapping a dielectric's normal-incidence reflectance — default 0.5 meaning four percent, the top of…
- Specular highlightThe reflected image of the source itself in a glossy surface — sharp and small on a polished one, spread and dim on a rough one, since ro…
- Specular reflectionReflection in which the outgoing angle equals the incoming angle about the surface normal, so the surface returns an image of what faces …
- SphereThe set of points equidistant from a center — the only closed surface with constant positive Gaussian curvature. An ellipsoid is a sphere…
- SpineThe main curved stroke of S and s, running from the upper terminal to the lower one. Its angle is the clearest single reading of a face's…
- Split lightingKey placed ninety degrees to the side and near eye level, so the terminator runs down the centre of the face: one half lit, the other in …
- Split-complementaryA hue paired with the two hues flanking its complement, roughly 150 and 210 degrees away. It keeps the tension of a complementary pair wh…
- Spot colorAn ink mixed to a specification and printed from its own plate rather than simulated out of process screens. Spot buys colors process can…
- Spot lightA source constrained to a cone, with a hot centre falling to a soft edge across a controllable penumbra angle. The cone is a masking of d…
- SpringbackThe elastic share of a bend returning the moment the tool releases. Every formed part relaxes back toward flat, so bends are deliberately…
- SprueThe main channel material travels down to reach the mould, and the solid stick of waste left standing in it afterwards. It is the trunk, …
- sRGBThe 1996 HP and Microsoft standard, written to describe a typical CRT and still the default assumption of the untagged web. Its gamut is …
- Stack-upThe accumulation of individual tolerances along a chain of features, resolving whether an assembly still fits at its extremes. Worst-case…
- StemThe principal stroke of a letter — the upright of b, l and H, the main diagonals of A and V. Stem width is the unit a face is built from:…
- STEPAn open ISO-standardized CAD exchange format carrying exact B-rep geometry — trimmed spline surfaces, topology, assemblies, units, and in…
- STLAn unstructured list of triangles, each written as three vertices and a normal. That is all: no units, no scale, no colour, no materials,…
- StressThe angle of the line joining the thinnest points of a round stroke — a fossil of the broad-nibbed pen's angle. Humanist and garalde face…
- StyreneWhite sheet plastic from 0.25 mm up, the standard body material for appearance models. It cuts by scoring and snapping, solvent-welds int…
- Subdivision SurfaceA smooth limit surface defined by a coarse control mesh — the cage — plus a refinement rule applied repeatedly. You edit the cage; the su…
- Subpixel RenderingTreating an LCD's red, green, and blue stripes as three independent samples, tripling horizontal resolution for a shape whose position is…
- SubsettingStripping a font file to the glyphs and tables a document actually needs. A Latin subset of a pan-European face can shed most of its byte…
- Subsurface scatteringLight entering a translucent medium, bouncing repeatedly below the surface, and leaving at a different point — skin, marble, milk, leaves…
- Subtractive colorMixing by removing wavelengths from a light source: each colorant absorbs part of the spectrum, so every addition darkens. Cyan, magenta,…
- Successive contrastThe shift induced by whatever the eye looked at just before. Fix on a saturated red, look away to white, and a cyan afterimage arrives: t…
- Support LoopAn extra edge loop placed close to a hard edge so subdivision cannot round it away — the tighter the loop, the sharper the result. It cos…
- Support structureSacrificial material printed under overhangs so molten or curing material has something to land on. Every support touches the part and le…
- Surface languageThe finishes, textures, and material transitions a product or family uses consistently enough that surface itself carries instruction — g…
- SweepMoving a profile along a path curve, generating surface as it goes, with the profile's orientation set by a rule — held fixed, kept norma…
- SymmetryCorrespondence of parts across an axis, a centre, or a translation. As a compositional principle it buys immediate stability and reads as…
T40
- Tabular figuresNumerals cast to a single advance width so digits stack in columns and a 1 occupies the same space as a 0 — the OpenType tnum feature, an…
- TactilityHow a surface reads to the hand: thermal conductivity, compliance, friction, micro-relief. Largely uncoupled from appearance — two surfac…
- TailA descending stroke, usually decorative or terminal rather than structural — the flourish of Q, the leg of R where it swings out, the des…
- Target sizeThe area that responds to a pointer or touch, measured in CSS pixels. WCAG 2.2 SC 2.5.8 Target Size (Minimum) sets 24×24 at Level AA, wit…
- Tear-outFibres or grain lifting and pulling away instead of shearing cleanly, almost always where the tool exits the work or crosses the grain. B…
- TensionThe felt pull between two elements, or between an element and the frame, produced by near-misses: an almost-alignment, an almost-touch, a…
- TerminalThe end of any stroke that does not finish in a serif. Named by shape: ball (Baskerville's a), teardrop, beak (the sharp spur on Perpetua…
- TerminatorThe locus on a surface where the light direction is tangent — where the normal is perpendicular to the incoming ray and direct illuminati…
- TessellationSubdividing a surface into more polygons at evaluation time, so there are vertices to move or shade. Displacement depends on it — a map c…
- TetradicTwo complementary pairs together, arranged as a square at ninety degrees or as a rectangle at unequal intervals. Four hues is more than m…
- Texel DensityTexture pixels per unit of surface, quoted as px/cm or px/m. It is the one thing that makes texture resolution consistent across an asset…
- Text spacingWCAG 2.1 SC 1.4.12, Level AA: no content or functionality is lost when the reader overrides line height to 1.5× the font size, spacing af…
- TextureThe character of a surface at a scale finer than its form — either tactile, meaning real relief the hand can register, or visual, meaning…
- Texture BakingPrecomputing a result into a texture indexed by UV, so it is looked up at runtime rather than evaluated. Anything can be baked: lighting,…
- Texture PaintingPainting colour and material straight onto a model's surface, projected through its UVs or into a volume, rather than into a flat image t…
- ThermoformingThe whole family of processes that soften sheet plastic with heat and shape it against a tool — by vacuum, by air pressure, between match…
- Third-angle projectionThe arrangement in which the plane sits between the viewer and the object, so each view appears on the side it is seen from: the right-si…
- Three-point lightingThe teaching setup: key to model the form, fill to control the shadow ratio, back light to separate subject from ground. It is a pedagogi…
- TilingBuilding a texture so that opposite edges match, letting it repeat over an unbounded surface from a small map. The technical requirement …
- TintA hue with white added — lighter and, in pigment, lower in chroma than the parent. Tinting raises value while pulling toward the achromat…
- ToleranceThe total permissible variation on a dimension — the distance between its upper and lower limits. Bilateral tolerance splits the band eit…
- ToneA hue with grey added — chroma reduced without a committed move in value. Toning is how a palette is made to sit together: most color tha…
- Tone mappingThe transform fitting a scene's luminance range into what a display can show — compressing highlights, holding mid-tone contrast, and dec…
- ToolpathThe curve a cutter's centre follows, offset from the wanted surface by the tool's radius and computed by CAM rather than drawn. It carrie…
- ToothThe fine mechanical roughness that lets a medium grab a substrate. Pastel, charcoal, and ink hold to a sheet's tooth; primer keys to a sa…
- TopologyIn mathematics, the properties of a shape preserved under continuous deformation: a mug and a torus are the same object, and every quad m…
- TorusThe surface swept by a circle revolved about a coplanar axis it does not intersect. Genus one: the canonical closed surface with a single…
- Total internal reflectionBeyond a critical angle, light travelling from a denser medium toward a less dense one stops refracting out and reflects entirely back in…
- TrackingA uniform adjustment to the space after every glyph in a run — CSS letter-spacing. Size-dependent: display type usually wants negative tr…
- TransitionalMid-eighteenth-century romans between the garaldes and the didones — Baskerville, Fournier, Bulmer, and the Romain du Roi ahead of them. …
- TranslucencyTransmission with scattering: light passes through but its direction is randomized on the way, so the material glows without carrying an …
- TransmissionThe fraction of light passing through a material rather than reflecting or being absorbed, bent by the IOR on entry and exit. Unlike opac…
- TransparencyTransmission without scattering: light crosses the material with its direction preserved — bent by the IOR, but coherently — so an image …
- TriA three-vertex face. Always planar, never ambiguous, and the only primitive a GPU actually rasterizes — every other face type is triangul…
- TriadicThree hues spaced 120 degrees apart: maximum spread with perfect symmetry, which is also the difficulty. Three equally strong hues compet…
- Trim SheetA single texture holding a strip of reusable details — panel edges, mouldings, plates, seams — which geometry is mapped onto by sliding U…
- True positionThe GD&T location control: a feature's axis or centre must fall inside a tolerance zone — usually a cylinder — centred on the exact locat…
- TurningCutting with a stationary tool against rotating work, producing forms symmetrical about a single axis. The lathe fixes the axis; the tool…
- TypefaceThe design — the set of letterforms and the relationships between them, across all its sizes, weights and widths. Garamond is a typeface.…
- Typographic hierarchyThe ordering of text by importance through typographic means — size, weight, case, colour, space, position, and the choice of face. Size …
U10
- UDIMA convention spreading one surface's UVs across a grid of numbered unit squares, each carrying its own texture file. The tile is encoded …
- UmbraThe part of a shadow from which the source is completely hidden — no direct light arrives from any point on the emitter. With a finite so…
- UndercutA region of a form that cannot be withdrawn along a given direction: any face whose normal turns back past the pull, so the mould locks o…
- UnicameralA script with one case — Arabic, Hebrew, Devanagari, Han, Hangul, Georgian mkhedruli. Most of the world's scripts are. Everything Latin t…
- Uniform connectednessA visibly connected region — elements joined by a line, a bar, or an unbroken fill — reads as a single unit. Palmer and Rock proposed it …
- Units per emThe resolution of a font's internal coordinate grid: how many design units divide one em. TrueType outlines conventionally use 2048, a po…
- UnityThe condition of a composition reading as one thing rather than an assembly of parts, produced by repetition, alignment, proximity, and a…
- USDA scene description with a composition engine: layers referenced, overridden, and combined non-destructively, so lighting can override an…
- UV SeamA cut in the UV mapping where the surface is torn open to lie flat. Every seam is a duplication: the vertices along it exist twice in the…
- UV UnwrapAssigning every vertex a coordinate in a 2D texture space so the surface can be laid flat and painted. Anything curved in two directions …
V16
- Vacuum formingHeating thermoplastic sheet until it sags, then pulling it down over a form with vacuum. Tooling is cheap — MDF, plaster, even a printed …
- ValueHow light or dark a color is, independent of hue and chroma — the one attribute that survives conversion to greyscale. Value does the str…
- Vanishing pointThe point on the picture plane where the projections of one set of parallel lines meet — the image of their shared direction at infinity.…
- VantageThe position a composition is constructed from — where the eye sits relative to the subject in height, distance, and angle. Vantage decid…
- VariableA platform's own named-value mechanism — a CSS custom property, a Figma variable, an iOS colour asset. It is where a token lands, not wha…
- Variable fontAn OpenType font holding a continuous design space rather than fixed instances: master outlines plus deltas, interpolated at render time …
- VectorAn image stored as geometry — paths with control points, fills, strokes — evaluated at output time, and so resolution-independent by cons…
- Veiling glareStray light scattered inside a lens or an eye that lands more or less uniformly across the image, adding a luminance floor everywhere. It…
- VentA deliberate escape path for the air the incoming material has to displace. Trapped air stops a fill dead and leaves a smooth-walled void…
- VertexA point in space, stored as coordinates, where edges meet. It is a mesh's only positional data — edges and faces are references to vertic…
- Vertical writing modeSetting text in columns running top to bottom, columns ordered right to left — the traditional mode for Japanese and Chinese, and current…
- Visual weightThe apparent pull of an element — how much of the eye it takes. Size, value contrast against the ground, saturation, density, complexity,…
- VoidSpace treated as a designed element rather than as leftover: a slot, a courtyard, the gap between a handle and the body it serves. A void…
- VolumeThe measure of the space a closed surface encloses, computed from a mesh by the divergence theorem — summing the signed tetrahedra from t…
- Vox-ATypIMaximilien Vox's 1954 nine-class scheme, adopted by ATypI in 1962 and extended to eleven. ATypI withdrew it in 2021: it conflates histori…
- Voxel ModelingWorking on a regular 3D grid of samples, each cell occupied or carrying a value. Topology changes are trivial — you are editing an array,…
W10
- WatertightA mesh that bounds a solid: closed, with no boundary edges, consistently oriented, and enclosing a definite inside. This is a fabrication…
- WCAGThe W3C's Web Content Accessibility Guidelines: testable success criteria filed under four principles and graded A, AA, or AAA. Conforman…
- WeightStroke thickness relative to the em — the amount of black a face puts on the page. The CSS scale runs 1–1000 with 400 as regular and 700 …
- WeldingJoining metals by melting the parent material of both parts so they fuse into one, usually with filler of the same alloy. The joint is as…
- White balanceThe decision about which spectrum in a scene should record as neutral, and the per-channel scaling that makes it so. It models the eye's …
- White pointThe chromaticity a space agrees to call neutral: D65 for sRGB and Display P3, D50 for print and ICC's profile connection space. It is a c…
- WidowA paragraph's last line stranded at the top of the next column or page, cut off from the text it belongs to. Some traditions also call a …
- WidthHow much horizontal space a face's letters occupy, as a percentage of normal — the wdth axis, exposed in CSS as font-stretch or font-widt…
- Word spacingThe space between words, set by the font's space glyph and adjustable via CSS word-spacing. It should be the smallest space that reliably…
- World spaceThe single global frame every object resolves into — the scene's origin and axes. A vertex's world position is its local position run thr…