leap day

Noun

leap day (plural leap days)

1. An extra day intercalated into a year, especially the day intercalated into the Julian calendar every fourth year and into the Gregorian calendar every fourth year excepting centuries not divisible by 400, usually reckoned as February 29th.
   • This yere leapt, and the leap day was the morrow after the feast Terminalia.1600, Livy, translated by Philemon Holland, The Romane Historie of T. Livius of Padua, Book XLV, Section xliv, 1232
   • The lunar cycle among the Chaldeans was called the saros and sara, from סהרא, sahara, the moon. This cycle it is said contained two hundred and twenty-three synodical months, or eighteen Julian years, ten days, when the same cycle or period contains five leap days, and eleven days when it contains...1820 July, Thomas Yeates, "Catalogue of Ancient Eclipses" in The Philosophical Magazine and Journal, Vol. LVI, No. 267, OCLC 1641414, p. 18

   Synonyms:

   leap-year day, bissext