Main Entry: ²fossil

Function: 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)