Paul Brewster • Link
Per the OED: catch, n
[ME. cache; prob. f. catch v. or n.1 The later ketch is analogous to keg for cag, kennel for cannel, etc. It may be the n. catch (in ME. cach(e) in sense 4
A catch is a part song, where the overlapping voices reveal a 'secret' phrase, often bawdy. Catches were popular in the late 17th and through the 18th century.
This page has an mp3 example of a modern catch you can listen to: "University of Michigan Men's Glee Club"
Another modern example: "Liverpool Street Station song"
Chart showing the number of references in each month of the diary’s entries.