/buy seks"til, -tuyl, bi-/ , adj.
1. containing or noting the extra day of leap year: The years 1980 and 1984 were both bissextile.
n.
2. See leap year .
[ 1585-95; bi ( s ) sextilis ( annus ) leap year, equiv. to bissext ( us ) BISSEXTUS + -ilis -ILE ]