The origin of encores

[snopes]

Comment: At a concert last night after the main performance ended I found
myself waiting for the encore. I then got to thinking: How did this
ritual of the audience clamoring for more as the band leaves the stage
originate? Is this one of those things that has just always been? or was
their one performance some time way back when in which the audience just
had to have another song?

I wouldn't know about that but "encore" is french for "again".

My guess is that it's a frenchism that came from english people watching french people call "encore" to hear the song again and they figured it was a word that meant "play the same song again"