(Latin) a musical instrument.

The earliest type of medieval polyphonic music, in which voices were added above a plainchant.

First form of polyphonic music. Originated around 1000 A.D. Included two part harmony. Developed out of Gregorian chant. ( Lesson 3, Page 2) HEAR IT

Earliest kind of polyphonic music, which developed from the custom of adding voices above a plainchant; they first ran parallel to it at the interval of a fifth or fourth and later moved more freely.

a polyphonic composition based on plainchant. In organum, a new line (the vox organalis) is added to the original plainchant line (the vox principalis) and uses the same text as the original. In settings of organum, sections of a chant that were originally sung by the choir remain as plainchant, so an alternation of polyphony and monophony results. See parallel organum, note-against-note organum, florid organum, and Notre-Dame organum.

Liturgical music, based on existing plainsong,, used to set prose; the earliest genre of medieval polyphonic music.

(or´-gun-oom). The earliest form of Medieval polyphony.

An organum is any one of a number of musical instruments which were the forerunners of the organ.