What does a mordent mean in classical music for the piano?
In music, a mordent is an ornament indicating that the note is to be played in 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. They occur most frequently in piano music (such as the repertoire of Frédéric Chopin) but occasionally turn up in orchestral scores. The term comes from the Latin mordere, meaning “to bite.” The mordent is thought of as a rapid single alternation between an indicated note, the note above (the upper mordent) or below (the lower mordent) and the indicated note again.