I was actually unaware that Mary Sue had shifted to be so broad. That's the first I've heard of it. Frankly, the term that annoys me is Marty Stu. Yeah. We really needed to make a gender specific version of this term... what are, Spanish? Mary Sue worked just fine for everybody. Marty Stu just sounds stupid.

But I'll contribute my own: PREQUEL. Prequel is not any work of fiction that chronologically takes place before any other work of fiction. It is a SEQUEL that chronologically takes place before a preceding work of fiction. Indiana Jones and the Temple of Doom is a prequel to Raiders of the Lost Ark. Indiana Jones and the Temple of Doom is not a prequel to Indiana Jones and the Last Crusade.