bissext
/ˈbɪsɛkt/ or /ˈbɪsɛks/Definitions
1. noun
A year that is divisible by 4 and also by 100, unless it is also divisible by 400, in which case it is a leap year.
“The calendar accounted for bissext years to maintain accuracy.”
2. adjective
Related to or characteristic of a bissext year.
“The bissext calendar was developed to account for the extra day.”