Heterophony

A heterophonic musical texture is one in which one or more instruments play (or one or more voices sing) a variation on the main melody simultaneously. Usually, this occurs while one instrument plays the melody unadorned. Heterophony is a defining characteristic of much of the world's music, including most traditional East Asian music (notably in Japanese Gagaku), which did not have harmony or polyphony before contact with Western music. It was also a characteristic of one tradition of American Hymnody in the 18th and 19th centuries, a tradition called "lining out" in which a song leader would sing a line of a hymn, and the congregation would answer, every member singing in the speed or style of their choice. Most notably, this style was adopted in early New Orleans jazz.

Bibliography

Garland Encyclopedia of World Music: Volume 7: East Asia: China, Japan, and Korea, 2003.
New Grove Dictionary of Jazz, 2001.