There are, I believe, two terms: "presentation pilot" which is a proof of concept episode to demonstrate what the show will look like before it's sold, and the "broadcast pilot," which is the first aired episode.
As far as Trek is concerned, "The Cage" and "Where No Man" were "presentation pilots" and "The Man Trap" was the "broadcast pilot."
I Spy also had it's "presentation pilot" shown later in the first season ("Affair in T'Sien Cha"), but most people call "So Long, Patrick Henry" the pilot, simply because it was the first broadcast episode.