a. The deeply forked tail of a swallow.
b. Something similar to the tail of a swallow.
2. See tailcoat.
3. Any of various colorful, widely distributed butterflies of the family Papilionidae, usually having an extension at the end of each hind wing that resembles the tail of certain swallows.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. 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.