Design Nomenclature / Systems & Spec
Design system
Also called DS, component library, pattern library, style guide
The whole of what a team shares in order to build one thing: tokens, components, patterns, usage guidance, and the process by which those change. The artefacts are the visible part and the smaller part — without a way of deciding, a design system is a component library with better documentation.
In practice
Means a Figma file to one team, an npm package to another, and a PDF to a third; the word survives because it is vague enough for all three to claim it. Ask what it is authoritative for, and what happens to someone who ignores it.