Webpack is a static module bundler (build tool) used for building modern JavaScript applications. It allows you to bundle all of your project's assets -- such as JavaScript files, CSS, images, and more -- into a single file or a few optimized files. This reduces the number of HTTP requests required to load resources, resulting in faster page load times.

In the context of Webpack, "static" means that bundling occurs at build time, before the code is run in the browser. With Webpack, all modules are bundled statically, meaning that all dependencies are resolved and bundled before the application is served to the user.

Webpack builds an internal dependency graph from one or more entry points and then combines every module your project needs into a single bundle file or few files.