nounpl. or·ga·na or or·ga·nums
Any of several types of medieval vocal polyphony, usually based on Gregorian chant.
Origin of organumMedieval Latin, from Late Latin, church organ, from Latin, instrument; see organ.
Variant of organon.
From Latin organum, from Ancient Greek á½„ÏÎ³Î±Î½Î¿Î½ (organon, “organ, instrument, tool").