leap day
Noun
Meaning
the name of the day that is added during a leap year
Source: WordNetSynonyms
Hypernyms
Examples
According to Dio Cassius, a leap day was inserted in 41 BC to ensure that the first market day of 40 BC did not fall on 1 January, which implies that the old 8-day cycle was not immediately affected by the Julian reform.
A leap day is observed because the Earth’s period of orbital revolution around the Sun takes approximately six hours longer than 365 whole days.
A leap day is added in various solar calendars (calendars based on the Earth's rotation around the Sun ), including the Gregorian calendar standard in most of the world.
As of March 1 ( O.S. February 17 ), when the Julian calendar acknowledged a leap day and the Gregorian calendar did not, the Julian calendar fell one day further behind, bringing the difference to 13 days.
As of March 1 ( O.S. February 19 ), when the Julian calendar acknowledged a leap day and the Gregorian calendar did not, the Julian calendar fell one day further behind, bringing the difference to 11 days.
Each Gregorian year has either 365 or 366 days (the leap day being inserted as 29 February), amounting to an average Gregorian year of 365.2425 days (compared to a solar year of 365.2422 days).