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Frontend Glossary

Frontend engineering · Tech stack

Component Library

Also called: UI library, UI kit, UI framework, Design system

A full set of ready-made UI components someone else built, like buttons, forms, and dialogs, that you can install and use right away. The style is consistent, and you don't have to build from scratch.

In detail

A component library is like a box of color-matched, ready-made building blocks. Buttons, inputs, tables, and dialogs are already built, with a consistent style, and details like keyboard support and accessibility are already handled. Common ones include Ant Design, Element Plus, MUI, and shadcn/ui.

It's not a framework. It sits on top of one: Ant Design is for React, Element Plus is for Vue, and you can't mix them across frameworks. shadcn/ui is a bit different: it copies the component source code straight into your project, so you can change it however you like.

A common beginner problem is mixing two or three component libraries in one project, which makes the style inconsistent and the bundle bigger. Pick one, write it into your rules file, and have the AI use the library's components first instead of hand-writing new ones every time.

Developer info
Term ID
eng-component-library
DOM selectors
No DOM cues. This concept isn't detected directly on a page.
Priority
1 · when several match at the same level, the higher priority wins
Version
v1 · updated Sep 29, 2026