noun
incidental music
Music that accompanies a play, film, or other performance, often serving as background or atmospheric music.
この劇の付随音楽は、有名な作曲家が手がけた。
The incidental music for this play was composed by a famous composer.
Compound of 付随 (fuzui, 'incidental, accompanying') and 音楽 (ongaku, 'music').