Definition from Wiktionary, the free dictionary
- The extra day in a leap year, currently February 29th in countries that use the Gregorian calendar and February 24th in the few communities using the Julian calendar; an extra day added to some other calendar to keep it synchronized with the solar year.
1820 July, “IV. Catalogue of Ancient Eclipses, with the Dates of their corresponding Eclipses at one and two Periods Distance. With Remarks. By Mr. Thomas Yeates.”, in The Philosophical Magazine and Journal, volume LVI, number 267, London: Printed by Richard and Arthur Taylor, Shoe Lane, OCLC 1641414, page 18:
- 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 four leap days, seven hours, forty-eight minutes, and one-fourth; in which time all the corresponding new and full moons and eclipses return again.
1852, Edward Greswell, Fasti temporis catholici, and Origines kalendariæ. [...] In Four Volumes, volume II, Oxford: At the University Press, OCLC 457298519, page 51:
- We observe then, with respect to the Julian cycle of leap-year, that, though we speak of it commonly as the cycle of the leap-year, it is in reality only the cycle of the leap-day. And this distinction is of much importance, especially to the present question. For the cycle of leap-year according to the Julian rule is one of four years, because the cycle of the leap-day in the Julian calendar is one of four also.
2000, Frank Morgan, “Leap Years”, in The Math Chat Book, [Washington, D.C.]: Mathematical Association of America, ISBN 978-0-88385-530-0, pages 9–10:
- According to our current calendar, on what day of the week will January 1 fall in the year 3000? in the year 1,000,000? in the year 101,000,000? […] In the thousand years from the year 2000 to the year 3000, there are 365,000 days, plus 250 leap days, minus 10 century leap days omitted, plus 3 leap days restored in the years 2000, 2400, and 2800, for a total of 365,243 days, or 57,177 weeks and 4 days. Since January 1 falls on a Saturday in the year 2000, it will fall four days later on a Wednesday in the year 3000.
2000, Mariano Veytia; Donald W. Hemingway and W. David Hemingway, comp., “Of the Other Three Manners of Calendars that the Indians Used”, in Ancient America Rediscovered: Including an Account of America's First Settlers who Left from the Biblical Towers of Babel at the Time of the Confusion of Tongues. First English Translation, Springville, Ut.: Bonneville Books, ISBN 978-1-55517-469-9, page 130:
- The rituals indicated all the festivals of the year, some of which were set and others movable; but with respect to the solar calendar, all were movable, because the ritual year only consisted of three hundred sixty-five days, and it did not have the leap days every four years, but rather at the end of its century they added thirteen days corresponding to the thirteen leap days the century included, which made up one entire week, and these days were dedicated to certain solemnities, […]
2002, Klaus Mainzer; Josef Eisinger, transl., The Little Book of Time, New York, N.Y.: Copernicus Books, ISBN 978-0-387-95288-8, page 20:
- According to the new leap rule, leap years are years whose last two digits are divisible by 4. To correct for the slightly shorter length of the solar year, 3 leap years are omitted every 400 years, and to that end, leap days are omitted in the secular years whose unit is not divisible by 4. Accordingly, the years 1700, 1800, and 1900 were not leap years, but 2000 was one again.
extra day in a leap year