Of, relating to, or being the period of geologic time from about 251 to 200 million years ago, the oldest period of the Mesozoic Era. The Triassic Period is characterized by the presence of the supercontinent Pangaea, the diversification of land life, the rise of dinosaurs, and the appearance of the earliest mammals. See Table at geologic time.
The Triassic Period.
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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.