A plug-in is an add-on module that extends Maya’s capabilities. You can create or purchase specialty plug-ins to customize Maya for a specific job.
Some features that are implemented as plug-ins are:
- File translators, which let you import and export various file formats.
- New tools, menu items, and MEL commands.
- New object types (nodes).
- Drivers for new devices.
For a more detailed list, see List of plug-ins included with Maya.