A Component Library is a collection of reusable user interface (UI) components that developers can use to build applications more efficiently. These components are pre-designed elements, such as buttons, forms, and navigation bars, which can be easily integrated into various projects. By using a component library, teams can maintain consistency in design and functionality across different parts of an application. Component libraries often come with documentation and guidelines, making it easier for developers to understand how to implement and customize the components. Popular examples of component libraries include Material-UI for React applications and Bootstrap, which is widely used for responsive web design.