Catch (music)

In music, a catch is a type of round or canon at the unison. That is, it is a musical composition in which two or more voices (usually at least three) repeatedly sing the same melody, beginning at different times. Generally catches have a secular theme, though many collections included devotional rounds and canons. In early collections the terms "catch" and "round" were interchangeable and, with part-songs and multi-voice canons, were all indexed as "songs".