Definition of "organum" [organum]

• Any of several types of medieval vocal polyphony, usually based on Gregorian chant. (noun)
• Variant of organon. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Hucbald's principal achievement, however, consists in having given a theoretic basis to the custom of adding another melody to the chant of the Church, which custom he called organum, or diaphonia (see COUNTERPOINT; HARMONY), thereby laying the foundation for polyphony which developed from it."
• "Nativitas gloriose virginis is a three-part organum, which is attributed to the medieval French composer Perotinus fl c.1200, who is also known as Pérotin."
• "He would have been peculiarly well fitted to give a truly scientific character to metaphysical studies, had it occurred to him to prepare the field by a criticism of the organum, that is, of pure reason itself."