A multiplex is a movie theater complex with multiple screens within a single complex. They are usually housed in a specially designed building. Sometimes, an existing venue undergoes a renovation where the existing auditoriums are split into smaller ones, or more auditoriums are added in an extension or expansion of the building. The largest of these complexes can sit thousands of people and are sometimes referred to as a megaplex.
The difference between a multiplex and a megaplex is related to the number of screens, but the dividing line is not well-defined; some say that 14 screens and stadium seating make a megaplex; others that at least 20 screens are required. Megaplex theaters always have stadium seating, and may have other amenities often not found at smaller movie theaters. Multiplex theatres often feature regular seating.