quaver: [15] Quaver was derived from an earlier and now obsolete Middle English quave ‘tremble’. This was of Germanic origin (Low German has the related quabbeln ‘tremble’), and probably started life as a vocal realization of the action of trembling. The use of the noun quaver for a short musical note (first recorded in the 16th century) comes from the original singing of such notes with a trill. [quaver etymology, quaver origin, 英语词源]