bissextile UK /bɪˈsɛkstɪl/US /bɪˈsɛks.taɪəl/adjective 1noun 1forms 1 adjective1 •Being or having an intercalary day, particularly the quadrennial leap day of the Julian and Gregorian calendars traditionally placed as a "second sixth" day before March 1st. noun1 •Synonym of leap year: a year with an intercalary day. formsbissextiles
