ETYM Old Eng. cadence, cadens, Late Lat. cadentia a falling, from Latin cadere to fall; cf. French cadence, Italian cadenza. Related to Chance.
A recurrent rhythmical series; SYN. cadency.
Rhythmical fall or modulation; Music, close of phrase, especially final chords.
In music, the closing progression of a chord sequence, usually of two chords linked by a note in common. A cadence defines the completion of a musical sentence in relation to a starting tonality.
A perfect cadence (V–I) corresponds to a full close, a plagal cadence (IV–I) corresponds to a weak close, and an imperfect cadence (I–V) corresponds to a half close. Transitional cadences, including the interrupted cadence (V–VI), resolving on a minor chord, and the Phrygian cadence are harmonically rhetorical flourishes.

To regulate by musical measure.