tr.v. in·ter·ca·lat·ed, in·ter·ca·lat·ing, in·ter·ca·lates
1. To insert (a day or month) in a calendar.
2. To insert, interpose, or interpolate.
[Latin intercalāre, intercalāt- : inter-, inter- + calāre, to proclaim; see kelə-2 in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.