Most application code examples in the **Overview** section of the documentation make use of regular, or static, modules. Modules define groups of components like [providers](/providers) and [controllers](/controllers) that fit together as a modular part of an overall application. They provide an execution context, or scope, for these components. For example, providers defined in a module are visible to other members of the module without the need to export them. When a provider needs to be visible outside of a module, it is first _exported_ from its host module, and then _imported_ into its consuming module.