波音或上波音（Mordent/Upper Mordent）是乐谱上一种标示装饰音的方式，与波音相反的是逆波音（Inverted Mordent）或下波音。

两种波音都是由三个音组成。当乐谱上出现波音符号时，以波音符号标示的音符为主音，演奏者必须快速地顺次弹奏主音、高一个(波音)或低一个(逆波音)音及主音一次。

弹奏波音的速度视乎演奏作品的速度而定，当弹奏以上波音及逆波音时，效果大致与此相同：

按此处试听波音效果，第一段使用了逆波音，第二段则无使用波音。

In music, a mordent is an ornament indicating that the note is to be played with a single rapid alternation with the note above or below. Like trills, they can be chromatically modified by a small flat, sharp or natural accidental. The term entered English musical terminology at the beginning of the 19th century, from the German Mordent and its Italian etymon, mordente, both used in the 18th century to describe this musical figure. The word ultimately is derived from the Latin mordere (to bite).