Of, relating to, or being the period of geologic time from about 488 to 444 million years ago, the second period of the Paleozoic Era. It is characterized by a major increase in marine biodiversity and the appearance of the supercontinent Gondwana. Some evidence suggests that the first land plants appeared at this time. See Table at geologic time.
The Ordovician Period.
[From Latin Ordovicēs, an ancient Celtic tribe of Wales, from Celtic Ordovices; see weik-3 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.