xhonzi said:

I think your personal definition is too narrow. A prequel is a sequel that takes place chronologically before the other movie.

Temple of Doom takes place prior to Raiders: Prequel. QED.

Casablanca and Close Encounters aren't sequels, and therefore aren't prequels, but I think you knew this.

And, as to an earlier question: Godfather II?

Since Temple's "prequelhood' rests entirely on that the date at the start is earlier than the date at the start of Raiders, and were those numbers different, it could have been a sequal, a sidequal, or a gritty reboot, I think Temple's status as a prequel is weak at best.

I'd also say Godfather 2 has a pretty weak claim to being a prequel. It's a sequel, that has some flashbacks in it. Is "The English Patient" a prequel to itself? Is "Last Crusade" a prequel?

I'm still straining my brain to think of any actual prequels worth a damn.