It's one of the extra things you can add on to the base project structure e.g. a Spring facet for Spring framework projects, or an Android facet for Android app

It's one of the extra things you can add on to the base project structure e.g. a Spring facet for Spring framework projects, or an Android facet for Android apps. https://www.jetbrains.com/help/idea/facet-page.html https://www.jetbrains.com/help/idea/facet-page.html