插曲 (chā qǔ): music played during a movie, play etc; incidental music; music played in a theatrical interlude; (fig.) incident; episode

The incidental music in this movie is very pleasant; after watching it, many viewers searched for its name online.

The director said this piece of incidental music was recorded in a small town in Italy, using local traditional instruments.

When the play reached the third act, a sad piece of incidental music played, and the audience was so moved that they shed tears.

The melody of this incidental music is very simple, but when paired with the movie scenes, it made that farewell scene even more touching.