1. Situated or running side by side; parallel.
2. Coinciding in tendency or effect; concomitant or accompanying.
3. Serving to support or corroborate: collateral evidence.
4. Of a secondary nature; subordinate: collateral target damage from a bombing run.
5. Of, relating to, or guaranteed by a security pledged against the performance of an obligation: a collateral loan.
6. Having an ancestor in common but descended from a different line.
1. Property acceptable as security for a loan or other obligation.
2. A collateral relative.
[Middle English, from Medieval Latin collaterālis : Latin com-, com- + Latin latus, later-, side.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 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.