1.NounAny species discovered first as a fossil and believed extinct, but which is later found living; an organism that has remained unchanged over geological periods. .mw-parser-output .defdate{font-size:smaller}
"The coelacanth and the dawn redwood are living fossils."
2.NounAny living species which very closely resembles fossil relatives in most anatomical details.
"Crocodiles are living fossils that haven’t changed their appearance much in millions of years."