A framework is a pre-built structure or set of rules and practices that help developers create web applications quickly and efficiently. Frameworks are usually open source software and contain a variety of tools and libraries that facilitate and accelerate development.

In web design, a framework usually refers to a library or set of code snippets that can be used for the design and development of websites. A framework can include a variety of features, such as a grid structure for layout design, pre-built styles for buttons and other UI elements, and pre-built code snippets for backend development.

Frameworks can significantly simplify and speed up the work of web designers, as they usually provide a variety of functions and tools that developers would otherwise have to laboriously programme themselves. A framework can also help to improve code quality and increase the scalability of the application.

There are a variety of frameworks for web design, such as Bootstrap, Foundation, Materialize and many others. The choice of the right framework depends on the specific requirements of the project, the experience of the developer and other factors.