In navies, the term originally appeared in the mid-1800s as a less-common synonym for gunboat.
More recently, a "gunship" is a helicopter to which machine guns and similar weapons systems have been mounted, or an airplane with heavy guns on board. (The etymology is that pilots often refer to their aircraft as "ships".) Examples include the AH-64 Apache and the AC-130 gunship.
Many science fiction games feature "gunship" as a class of armed spacecraft, although being imaginary there is no set rule for size or armament.
Gunship is a computer game simulating helicopter gunships.