Quaver

1. To tremble; to vibrate; to shake.
2. To utter with quavers.
3. A shake, or rapid and tremulous vibration, of the voice, or of an instrument of music.
4. An eighth note. See Eighth.
5. Especially, to shake the voice; to utter or form sound with rapid or tremulous vibrations, as in singing; also, to trill on a musical instrument