See fossil in Webster's New World College Dictionary
noun
Obsolete any rock or mineral dug out of the earth
any hardened remains or imprints of plant or animal life of some previous geologic period, preserved in the earth's crust, including petrified wood and various resins
anything fossilized or like a fossil
a person who is old-fashioned or has outmoded, fixed ideas
adjective
of, having the nature of, or forming a fossil or fossils
belonging to the past; unchanged by progress; antiquated
See fossil in American Heritage Dictionary 4
(fŏsˈəl)
noun
A remnant or trace of an organism of a past geologic age, such as a skeleton or leaf imprint, embedded and preserved in the earth's crust.
One, such as a rigid theory, that is outdated or antiquated.
Linguistics
a. A word or morpheme that is used only in certain restricted contexts, as kempt in unkempt, but is otherwise obsolete.
b. An archaic syntactic rule or pattern used only in idioms, as so be it.
adjective
Characteristic of or having the nature of a fossil.