There are other vehicles called "Starship" that aren't actual starships either - the Beechcraft Starship (a twin-engined turboprop pusher aircraft) or "The Star

There are other vehicles called "Starship" that aren't actual starships either - the Beechcraft Starship (a twin-engined turboprop pusher aircraft) or "The Starship" (a Boeing 720 used by Led Zeppelin and other bands). It's a proper noun chosen as a name or model designation for the vehicle, as opposed to a common noun describing the vehicle itself (a spacecraft).