antiphon

n. hymn sung in alternate parts, responsive song

This article is about the musical term. See Antiphon (person) the orator of ancient Greece. An antiphon is a response, usually sung in Gregorian chant, to a psalm or some other part of a religious service, such as at Vespers or at a Mass. This meaning gave rise to the antiphony style of singing, see call and response.
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Noun
1. a verse or song to be chanted or sung in response
(synonym) antiphony
(hypernym) religious music, church music
(hyponym) gradual

n. antiphon, hymn sung in alternate parts, responsive song

(n.)
A verse said before and after the psalms.
  

(n.)
A musical response; alternate singing or chanting. See Antiphony, and Antiphone.