n.
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 )