adj. Of, relating to, or being the period of geologic time from about 416 to 359 million years ago, the fourth period of the Paleozoic Era. The Devonian Period is characterized by the development of lobe-finned fishes, the appearance of amphibians and insects, and the first forests. See Table at geologic time. n. The Devonian Period. [After Devon, a county of southwest England.] |
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