I. ˈfä-səl adjective
Etymology: Latin fossilis obtained by digging, from fodere to dig — more at bed
Date: 1604
1. : preserved from a past geologic age
fossil plants
fossil water in an underground reservoir
2. : being or resembling a fossil
3. : of or relating to fossil fuel
II. noun
Date: 1736
1. : a remnant, impression, or trace of an organism of past geologic ages that has been preserved in the earth's crust — compare living fossil
2.
a. : a person whose views are outmoded : fogy
b. : something (as a theory) that has become rigidly fixed
3. : an old word or word element preserved only by idiom (as fro in to and fro )