bissextile

[bahy-seks-til, -tahyl, bi-]

adjective

containing or noting the extra day of leap year: The years 1980 and 1984 were both bissextile.

noun

leap year.

Origin of bissextile

1585–95; < Late Latin bi(s)sextilis (annus) leap year, equivalent to bissext(us) bissextus + -ilis -ile

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for bissextile

Historical Examples of bissextile

This fourth year was denominated Bissextile, because the sixth day before the Kalends of March was reckoned twice.
Letters on Astronomy
Denison Olmsted
Can we therefore believe that the Egyptians before this period were ignorant of the bissextile intercalation?
The Geography of Strabo, Volume III (of 3)
Strabo
The bissextile is known to have been used by the Mayas, Tzendals, and Quichés, and it was probably common.
Ancient America, in Notes on American Archaeology
John D. Baldwin
The fourth year was bissextile, and the dominical letters were F, E; the following year D, and so on.
Encyclopaedia Britannica, 11th Edition, Volume 4, Part 4
Various

British Dictionary definitions for bissextile

bissextile

adjective

(of a month or year) containing the extra day of a leap year

noun

a rare name for leap year

Word Origin for bissextile

C16: from Late Latin bissextilis annus leap year, from Latin bissextus, from bi- 1 + sextus sixth; referring to February 24, the 6th day before the Calends of March

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for bissextile

1580s (n.); 1590s (adj.), in reference to Roman leap year, from Late Latin (annus) bissextilis "leap year," literally "the twice sixth-day," because the sixth day before the Calends of March was doubled.