(of a month or year) containing the extra day of a leap year
noun
2. a rare name for leap year
Word origin
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
bissextile in American English
(bɪsˈsɛkstɪl; bɪsˈsɛkstəl; bɪsˈsɛksˌtaɪl)
adjective
1.
denoting the extra day (February 29) of a leap year
2.
designating or of a leap year
noun
3. Rare
leap year
Word origin
LL bisextilis, containing an intercalary day < bisextus < bis, twice (see bi-1) + sextus, sixth: Feb. 24 (sixth day before the calends of March) was reckoned twice every fourthyear