TRILL, or PLAIN SHAKE and GRUPPO, in music. The first is defined to be a shake upon one note only, in the making whereof the scholar is directed to sing the first of the examples, (Plate CCCXIII. fig. 2.) beginning with the first crotchet, and beating every note with the throat upon the vowel o, to the last breath. The gruppo (as described by Playford) appears to be no other than the shake now practised, and which consists in the alternate prolation of two tones in juxtaposition to each other, with a close on the note immediately beneath the lower of them. The trill (says Playford) being the most usual grace, is made in closes or cadences; and when on a long note, exclamation or passion is expressed there, the trill is made in the latter part of such note; but most usually upon binding notes, and such as precede the closing note. Notwithstanding this, Mr Hawkins is of opinion that the trill is rather a defect than an ornament in singing; as being nothing more than the intermitted prolation of a single tone.