Design Nomenclature / Form & Geometry
Interpolation
Also called lerp, blend, tween, in-between
This entry has not been translated yet and is shown in English.
Generating intermediate values between known ones — points along a curve, frames between keys, a surface between defining sections. Linear interpolation blends two values proportionally; higher-order schemes also match tangents or curvature, so the result passes through smoothly rather than in a chain of straight segments. Every spline evaluation and every morph is this under another name.
In practice
A variable font's weight axis is interpolation between masters — which is exactly why the masters must be compatible: same point count, same order, same start point. Extrapolation is the same machinery outside the known range, and far less safe.