Here’s the official regs:
https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart-E
I will try to list the different types of stations but I apologize for missing any:
Base Station, Control Station, Fixed Station, Mobile Station, Portable Station, Repeater Station.
Unless regulated specifically, Portable Stations are a subset of Mobile Stations. Handhelds are simply a type of Portable Stations. There are a very few regulations that apply to handhelds to the exclusion of other station types.
This forum has a long and possibly inconclusive discussion about Fixed Stations.