/deuh voh"nee euhn/ , adj.
1. Geol. noting or pertaining to a period of the Paleozoic Era, 405 to 345 million years ago, characterized by the dominance of fishes and the advent of amphibians and ammonites. See table under geologic time .
2. of or pertaining to Devonshire, England.
n.
3. Geol. the Devonian Period or System.
[ 1605-15; Devoni ( a ) Devon + -AN ]