<p><strong>Noun</strong></p><ul><li>any remains, impression, or trace of a living thing of a former geologic age, as a skeleton, footprint, etc.</li><li>a markedly outdated or old-fashioned person or thing</li><li>a linguistic form that is archaic except in certain restricted contexts, as nonce in for the nonce, or that follows a rule or pattern that is no longer productive, as the sentence So be it.</li></ul><p><strong>Adjective</strong></p><ul><li>of the nature of a fossil: fossil insects</li><li>belonging to a past epoch or discarded system; antiquated: a fossil approach to economics</li></ul>