Finale is a term used in classical ballet to mean “the end of a ballet.” Finale is not exclusive to ballet, as its used commonly in English and it’s originating language, Italian, to describe the end of something.
In terms of classical ballet, a finale is usually the last dance or section of a ballet that will often sum up the entire story or movement. Usually the finale is a scene that will be either high energy or drama along with equally dramatic music.
A finale can sometimes be in the middle of a ballet as well. A coda of a pas de deux could be considered a finale since it is the end of the pas de deux.