The quick repetition of one or two pitches.

Quick repetition of the same note or the rapid alternation between two notes.

(Italian: 'trembling'). The quick repetition of a single note, usually used in string playing.

Rapid repetition of the same note. If the note value for repetition is shown as strokes on the stem of a minim, it is measured tremolo. Tremolo on the drums is called roll.