Definition of "box set"

Related musical or video recordings that are gathered on multiple items of the same kind of media (compact discs, DVDs, VHS tapes, etc.) and placed in a box to be sold as a unit.  examples

A set of related books from a particular author or genre that are contained within a box.  examples

(theater) A set with a proscenium arch stage and three walls, creating the appearance of an enclosed room.  examples