Wordnet 3.0
NOUN (1)
1.
vocal music for several voices in independent parts (usually performed without accompaniment);
WordNet (r) 3.0 (2006):
part music
n 1: vocal music for several voices in independent parts
(usually performed without accompaniment)
Moby Thesaurus II by Grady Ward, 1.0:
18 Moby Thesaurus words for "part music":
duet, duettino, duo, ensemble music, ensemble singing, octet,
part singing, part song, polyphonic music, quartet, quintet,
septet, septuor, sestet, sextet, terzet, terzetto, trio