leap year

Meaning

Noun

• A year in the Julian or Gregorian calendars with an intercalary day added to February, used to adjust for the extra hours of the solar year; a 366-day year.
• Any other year featuring intercalation, such as a year in a lunisolar calendar with 13 months instead of 12, used to maintain its alignment with the seasons of the solar year.

Related

Similar words

• bissextile, bissext

Origin

• From Middle English lepe yeer, lep ȝere, lyp ȝere, equivalent to leap + year. Probably from a much older formation related to the Old Norse hlaup-ár, Old English mōnan hlȳp (compare Latin saltus lunae used in reckoning lunar months on a 19-year cycle). The name is presumably related to the phenomenon that any fixed date of a 365-day calendar advances one weekday each year but every date of a 366-day year (on modern reckonings after February 29) advances by two weekdays instead. For example, Christmas (December 25) fell on a Saturday in 2004, a Sunday in 2005, a Monday in 2006, and a Tuesday in 2007 but then "leapt" over Wednesday to fall on a Thursday in 2008.