containing or noting the extra day of leap year: The years 1980 and 1984 were both bissextile.
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How to use bissextile in a sentence
I refer you to Montucla, if you have any doubt about the Egyptian year being of 365 days without bissextile of any kind.Personal Recollections, from Early Life to Old Age, of Mary Somerville | Mary Somerville
The fourth year was bissextile, and the dominical letters were F, E; the following year D, and so on.
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
Can we therefore believe that the Egyptians before this period were ignorant of the bissextile intercalation?
This fourth year was denominated bissextile, because the sixth day before the Kalends of March was reckoned twice.Letters on Astronomy | Denison Olmsted
British Dictionary definitions for bissextile
(of a month or year) containing the extra day of a leap year
a rare name for leap year
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