Fossil

noun

(L. fossilis: dug out) Generally, anything ancient, especially if it is discovered buried below ground (e.g. fossil fuel, fossil soil). The remains of a once-living organism, generally taken to be one that lived prior to the end of the last glacial period, i.e. fossils are older than 10 000 years. The term includes skeletons, tracks, impressions, trails, borings and casts. Fossils are usually found in consolidated rock, but not always (e.g. woolly mammoths living 20 000 years ago were recovered from the frozen tundra of Siberia). In its original sense, fossil meant anything dug up from the earth, including ores, precious stones, etc. The modern use of the word dates from the late 17th century. See also living fossil; and trace fossil.