mordent

A mordent is a rapid ornament consisting of the main note, the note below, and a return to the main note. It adds a quick snap or bite to a note. The upper mordent (also called an inverted mordent or pralltriller) alternates with the note above instead. In Baroque music, mordents were part of a rich vocabulary of ornaments that performers were expected to add even when not explicitly written. The speed of a mordent depends on the tempo and style of the piece — in slow movements, it may be leisurely, while in fast passages it is almost instantaneous. C.P.E. Bach's treatise on keyboard playing provides detailed instruction on ornament execution.