Divertissement is a classical ballet term meaning “enjoyable diversion.” A divertissement is a grouping of dances called “entrées” that are part of classical ballets. These short dances are typically added to a ballet to display more dancers’ talents whether as solos or in a group piece. The divertissement isn’t always necessarily vital or directly related to the story, but would make for many shorter ballets without them!
For example, the Chinese, Russian, Arabian, and Spanish dances in the second act of The Nutcracker are divertissement. Imagine a Nutcracker without them, the second act would be very short.