Inserted or introduced among others in the calendar; as, an intercalary month, day, etc.; -- now applied particularly to the odd day (Feb. 29) inserted in the calendar of leap year. See Bissextile,
- Inserted in the calendar to make the calendar year correspond to the solar year. Used of a day or month.
- Having such a day or month inserted. Used of a year.
- Inserted between other elements or parts; interpolated.