Of or pertaining to someone named Gregory.
Gregorian calendar the calendar introduced in 1582 by Pope Gregory XIII, as a modification of the Julian calendar.To bring the calendar back into line with the solar year, 10 days were suppressed, and centenary years were only made leap years if they were divisible by 400. Scotland adopted the Gregorian calendar in 1600, but England and Wales did not follow suit until 1752 (by which time 11 days had to be suppressed). At the same time New Year's Day was changed from 25 March to 1 January, and dates using the new calendar were designated ‘New Style’.
Gregorian chant church music sung as a single vocal line in free rhythm and a restricted scale (plainsong), in a style developed for the medieval Latin liturgy, and named after St Gregory the Great, who is said to have standardized it.