1. The lower jaw of a vertebrate animal.
2. Either the upper or lower part of the beak in birds.
3. Any of various mouth organs of invertebrates used for seizing and biting food, especially either of a pair of such organs in insects and other arthropods.
[Middle English, from Old French, from Late Latin mandibula, from Latin mandere, to chew.]
man·dibu·lar (-dĭbyə-lər) adj.
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.