From Longman Dictionary of Contemporary EnglishGregorian calendarGre‧go‧ri‧an cal‧en‧dar /ɡrɪˌɡɔːriən ˈkæləndə $ -dər/ noun [singular] TMCthe system of arranging the 365 days of the year in months and giving numbers to the years from the birth of Christ, used in the West since 1582
Examples from the Corpus
Gregorian calendar• All I know, like the protestors when the Julian became the Gregorian calendar, is that I must have missed something.Origin Gregorian calendar (1600-1700) Because it was introduced by Pope Gregory XIII 