While I was fixing up the Glossary yesterday, I added two new requested definitions:

McGUFFIN
Often associated with Hitchcock, PageWise has a good definition: A device or plot element that catches the viewer’s attention or drives the plot. It is generally something that every character is concerned with. The McGuffin is essentially something that the entire story is built around and yet has no real relevance. That is, it’s what the movie says it’s about, even though it really isn’t. In the first Charlie’s Angels, the McGuffin was stolen voice-identification software; in the second, it was a Federal Witness Protection List. In both cases, the villain’s real motivation was greed and revenge. In early drafts of Full Throttle, the Angels had to retrieve a glowing vial labelled “McGuffin Industries.”

SET-PIECE
A scene or sequence with escalated stakes and production values, as appropriate to the genre. For instance, in an action film, a set-piece might be a helicopter chase amid skyscrapers. In a musical, a set-piece might be a roller-blade dance number. In a high-concept comedy, a set piece might find the claustrophobic hero on an increasingly crowded bus, until he can’t take it anymore. Done right, set-pieces are moments you remember weeks after seeing a movie.