gymel

In medieval and early Renaissance English polyphonic music, gymel (also gimel or gemell) is the technique of temporarily dividing up one voice part, usually an upper one, into two parts of equal range, but singing different music. Often the two voices sing a passage of intricate polyphony, beginning and finally converging on a unison, and often, but not always, the other voices drop out for a time.

While the earliest use of gymel seems to have been around the mid-14th century, the earliest notated gymels survive from approximately 1430. It is probable that some earlier notated examples have been lost, since the vast majority of English manuscript sources from before the 1530s were destroyed during the Dissolution of the Monasteries by Henry VIII. Indeed, the earliest surviving notated examples are from continental sources.