- A year in the Gregorian calendar having 366 days, with the extra day, February 29, intercalated to compensate for the quarter-day difference between an ordinary year and the astronomical year.
- An intercalary year in a calendar.
(plural leap years)
- In the Gregorian calendar, a year having 366 days instead of the usual 365, with the extra day added to compensate for the fact that the Earth rotates approximately 365.25 times for each revolution it makes around the Sun.
- In the Jewish calendar or other lunisolar calendars, a year having 13 months instead of 12, with the extra month added because 19 solar years is approximately 19*12+7 lunar months.
So called from the fact that, while a fixed date in the Gregorian calendar normally advances one day of the week from one year to the next, in a leap year the day of the week will advance two days (from March onwards) due to the extra day inserted at the end of February (thus "leaping over" one of the days in the week). For example, Christmas Day fell on Saturday in 2004, Sunday in 2005, Monday in 2006 and Tuesday in 2007 but then "leapt" over Wednesday to fall on a Thursday in 2008.
- attributive form of leap year, noun.
- Stateside, a presidential election is a leap-year event.