Any of various carnivorous pelycosaurs of the genus Dimetrodon of the Permian Period, having long spines on the back that supported a sail-like structure, and powerful jaws with sharp teeth.
[New Latin Dimetrodōn, genus name : Greek di-, two; see DI-1 + Greek metron, measure; see mē-2 in the Appendix of Indo-European roots + Greek odōn, tooth (from its having two different kinds of teeth); see dent- in the Appendix of Indo-European roots.]
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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.