ornaments

Note or series of notes used to embellish or lend variety to a melody.

appoggiatura

A short accented note played just before a principal note but immediately released.

trill

Quite rapid succession of one note with a note a semitone or a full tone above it.

turn

Series of brief notes around a principal note.

mordent

Rapid succession of two notes: the principal note and the upper mordent, or the principal note and the lower mordent, if the mordent is barred.