Intercalate v. t. (past & past part. intercalated; pres. part. intercalating)
(Chron.) To insert, as a day or other portion of time, in a calendar.
To insert among others, as a verse in a stanza; specif. (Geol.), to introduce as a bed or stratum, between the layers of a regular series of rocks. "Beds of fresh-water shells... are intercalated and interstratified with the shale."