organum definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
organum definition by American Heritage Dictionary
noun pl. or·ga·na or or·ga·nums
Any of several types of medieval vocal polyphony, usually based on Gregorian chant.
Origin: Medieval Latin, from Late Latin, church organ, from Latin, instrument; see organ.
noun pl. or·ga·nums
Variant of organon.