plainchant
Longman Dictionary of Contemporary English 5++LDOCE 5++plain·chant /ˈpleɪntʃɑːnt $ -tʃænt/ noun [uncountable] APMplainsong 〔旧时教堂中齐唱而无伴奏的〕素歌，单旋律圣歌
Examples from the Corpus
plainchant• A comparable example in the West is the Latin liturgy set to plainchant.plain·chant nounChineseSyllable
Corpus plainsong
See plainsong for more
plainchant
plain‧chant /ˈpleɪntʃɑːnt $ -tʃænt/ 
noun [uncountable]
plainsong
plain‧song /ˈpleɪnsɒŋ $ -sɒːŋ/ (also plainchant) noun [uncountable]
a type of old Christian church music in which people sing a simple tune without musical instruments
| I |
noun [uncountable]plainsong
| II |
(also plainchant) noun [uncountable]a type of old Christian church music in which people sing a simple tune without musical instruments