In*ter`ca*la"tion (?), n. [L. intercalatio: cf. F. intercalation.]
The insertion of a day, or other portion of time, in a calendar.
The insertion or introduction of anything among others, as the insertion of a phrase, line, or verse in a metrical composition; specif. Geol., the intrusion of a bed or layer between other layers.
Intercalations of fresh-water species in some localities.
© Webster 1913.