Definition of: fossil

(fos′əl, fôs′-) noun Paleontol.
1. The actual remains of plants or animals, preserved in the rocks of the earth's crust; also, material evidences of early organisms, as in petrified forms, coprolites, casts, impressions, imprints, etc.
2. Geol. One of certain inorganic objects or substances which in extinct or mineralized forms preserve in themselves records of the natural activities or phenomena of ancient geological ages, as solidified ripple marks.
3. Buried records of human activities, even within historic times.
4. Colloq. A person or thing that is behind the times, antiquated, or out of date.
—adjective
1. Dug out of the earth; petrified.
2. Of or like a fossil; outworn; antiquated. [<F fossile <L fossilis dug up <fossa. See FOSS.]