In*ter"ca*la*ry [L. intercalaris, intercalarius: cf. F. intercalaire. See Intercalate.]
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, n.
Introduced or inserted among others; additional; supernumerary.
This intercalary line . . . is made the last of a triplet.
Intercalary day Med., one on which no paroxysm of an intermittent disease occurs.
© Webster 1913.