I'm reminded of the impression I constantly received when I first watched TOS - namely, that the Enterprise type was the biggest and best thing Starfleet had, and moreover, the only real "Starship" design. Sure there were other types of ships, but they were just spaceships, not fancy Starships.
I dunno... the one episode where they really played up the starship / spaceship difference was "Bread and Circuses", and there they were comparing Enterprise
to the non-Starfleet merchant vessel SS Beagle
. So while the Enterprise
type might have indeed been the cream of the crop at the time, I don't think they were ever intended to be the only real starship design. Any front-line Starfleet vessel probably has the right to be called a "starship".
(I know they only ever showed
starships of the same type as Enterprise
, but... budget.
Actually, that's right! Republic belongs on the list too!
Now, to answer your question:
KIRK: Ensign Garrovick is a ship-command decision. You're straying out of your field, Doctor.
MCCOY: Am I? I was speaking of Lieutenant James T. Kirk of the starship Farragut.
From "The Immunity Syndrome"
SPOCK: Doctor, even I, a half-Vulcan, could hear the death scream of four hundred Vulcan minds crying out over the distance between us.
MCCOY: Not even a Vulcan could feel a starship die.
From "Court Martial"
COMPUTER: Ship nomenclature. Specify.
KIRK: United Starship Republic, number 1371.
Which is why I don't personally think that any ship referred to as a starship automatically means she's the same class as Enterprise
. Sorry. YMMV, of course.
's commissioning plaque notwithstanding, of course. Since that was there from the earliest days of the series, I think that's just one of the things that hadn't really been ironed out yet (like Earth vs. Federation ship), and at best refers to "Starship Class" the same way you might refer to a "destroyer class" vessel IRL, but then within the destroyer classification, you'd have, say, St. Laurent