/ ˈfɒsl; NAmE ˈfɑːsl/ noun
1.
the remains of an animal or a plant which have become hard and turned into rock :
fossils over two million years old
2.
( informal , disapproving ) an old person, especially one who is unable to accept new ideas or adapt to changes
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WORD ORIGIN
mid 16th cent. (denoting a fossilized fish found, and believed to have lived, underground): from French fossile , from Latin fossilis dug up, from fodere dig.