block booking
n.— «As Ladd explained in Blockbuster, Star Wars got into the theaters because of a now illegal practice called “block booking,” which involved studios essentially holding a big movie hostage in exchange for theaters agreeing to play one of the studio’s smaller films. Fox told theater owners if they wanted “The Other Side of Midnight,” a potboiler based on the Sidney Sheldon bestseller, they had to show this little movie “Star Wars” too.» —“Star Wars: A Box Office History Lesson” by David Konow Tom’s Games Aug. 13, 2008. (source: Double-Tongued Dictionary)