Parts

Parts are the polygon version of point selection sets. (One distinction, however, is that a polygon can be assigned to only one part name, while a point can be a member of multiple selection sets.) You can quickly select a user-defined set of polygons by name as you would with surface names. This feature operates independently and in parallel with surface naming.

The Surfaces To Parts command (Selection > Selection Sets > Surfs to Parts) can convert surfaces to part names. The Part names are taken from the original Surface name.