plainchant means synonym of plainsong. Lexicurio rates it Rare gem — a strength score of 84 out of 100.
Why “plainchant” is a great word
PLAINCHANT — [Noun] The monophonic, unaccompanied liturgical chant of the Western Christian Church. From French plain-chant (literally 'plain song'), a calque of Latin cantus planus ('plain song'); first attested in English in 1740. Unlike polyphony, which weaves multiple, independent lines into a complex tapestry, or a chorale, which denotes a sturdy, harmonized hymn, plainchant is a single, unadorned thread of melody. It is the resonant hum in a stone vault at dawn, the measured breath of a solitary voice tracing a neume in the air, the collective murmur of a discipline older than harmony itself—a solitary line of prayer, seeking a path upward through the silence from which it came.
Etymology
From French plain-chant, from plain + chant, calque of Latin cantus planus.
noun
- Synonym of plainsong.