Component

A component is a reusable unit of UI — design and code wrapped together — that a design system delivers as a self-contained building block. A button, an input, a tab, a modal: each is a component, with defined variants, states, and an API that consumers compose with.

The component is the unit of reuse, but it's also the unit of decision: what does it accept as props, what does it expose as slots, what's its accessibility contract. A well-designed component lets product teams move fast without duplicating effort or compromising consistency. Most modern design systems (Material, Polaris, Carbon, Atlassian) ship 40–80 of them, organised loosely along atomic design lines.

Related: Component library · Design tokens · Variants · Component states