Толковый словарь английского языка Oxford English Reference - quaver

v. & n. --v. 1 intr. a (esp. of a voice or musical sound) vibrate, shake, tremble. b use trills or shakes in singing. 2 tr. a sing (a note or song) with quavering. b (often foll. by out) say in a trembling voice. --n. 1 Mus. a note having the time value of an eighth of a semibreve or half a crotchet and represented by a large dot with a hooked stem. Also called eighth note. 2 a trill in singing. 3 a tremble in speech. Derivatives quaveringly adv. Etymology: ME f. quave, perh. f. OE cwafian (unrecorded: cf. cwacian QUAKE)