Any of various fishes lacking jaws, including the hagfishes and the lampreys and many extinct groups, such as the ostracoderms.
[A-1 + Greek gnathos, jaw; see genu-2 in the Appendix of Indo-European roots + -AN1.]
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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.