A word to refer to the "The Far Side of the World" part in the film title Master and Commander: The Far Side of the World (MC:FSW) might be subtitle. By here, the "Master and Commander" part is called title. But so is the full title MC:FSW.
I tried negating the prefix with supertitle and surtitle, which are opposites of another meaning of subtitle. I also considered location: I'm trying to find a word to describe the first part of a title, so I looked for pretitle. The uses I found meant "coming in a film before or during its opening credits."
Is there another word that means precisely "title but not subtitle"?