noun
Gregorian calendar
The solar calendar introduced by Pope Gregory XIII in 1582, now the internationally accepted civil calendar. In Japanese, it is the standard calendar for most non-traditional purposes.
日本では明治6年からグレゴリオ暦が採用された。
Japan adopted the Gregorian calendar in 1873.
グレゴリオ暦では、うるう年は400年
In the Gregorian calendar, leap years occur 97 times every 400 years.