A more thorough explanation:

Definition: Block-booking is a practice used by film distributors in the licensing or use of movies. It involves conditioning the license or use of a package or block of films on the acceptance of an entire package, which typically includes unwanted or inferior films. This practice is considered illegal and violates the Sherman Act.

Example: Let's say a movie theater wants to show a popular movie that is distributed by a company that practices block-booking. The distributor may require the theater to also show several other movies that are not as popular or desirable in order to get the license for the popular movie. This forces the theater to show movies they may not want to show, and it limits the choices available to moviegoers.

This example illustrates how block-booking can limit competition and consumer choice. It also shows how the practice can be harmful to smaller theaters that may not have the resources to show a large number of movies.