Gregorian chantGregorian chant
a ritual plainsong, monophonic and unmeasured, traditionally codified by Pope Gregory I, and formerly widely used in the Roman Catholic Church
nounRoman Catholic Church
An unaccompanied, monophonic liturgical chant.
Origin of Gregorian chantAfter Saint Gregory I.
Named after Pope Gregory I (540-604), and certainly dating back to that time in some form, but the exact origin is a matter of ongoing research.