An intermission, also known as an interval in British and Indian English, is a recess between parts of a performance or production, such as for a theatrical play, opera, concert, or film screening. It should not be confused with an entr'acte, which, in the 18th century, was a sung, danced, spoken, or musical performance that occurs between any two acts, that is unrelated to the main performance, and that thus in the world of opera and musical theater became an orchestral performance that spans an intermission and leads, without a break, into the next act.
Intermission screen frame during a 1912 film. Used in motion picture theaters as announcement
Entr'acte means 'between the acts'. It can mean a pause between two parts of a stage production, synonymous to an intermission, but it more often indicates a piece of music performed between acts of a theatrical production.
Pendant l'entracte (During the entr'acte): lithography by Alexandre Lunois published in L'Artiste (1894).