That's not the same thing. The term "Star Trek" has come to mean any story that takes place in that Universe, whether there's any trekkin' involved or not. It would be a bit weird to call a movie Foundation if it doesn't involve the Foundation somehow. Robots Of Dawn and Robots And Empire-- and Caliban and its sequels for that matter-- and a bunch of other books take place in the same Universe as Foundation, but they're not called Foundation.