tent pole
n.— «The industry term for a movie (usually but not always a franchise flick) that a major studio expects will be a blockbuster (but often isn’t), “tent pole” is a particularly evocative buzzword to toss around these days, especially for those brushing up on ancient texts or history in preparation for a pitch meeting with a major studio.» —“Studios scurry to make movies with international legs” by Jennie Punter Globe and Mail (Toronto, Can.) May 31, 2004. (source: Double-Tongued Dictionary)