More from this author. 1  Largest World Cities: 2014. 2  World Urban Areas Population and Density: A 2012 Update. 3  Largest Cities in the World: 2016. 4  Largest 1,000 Cities on Earth: World Urban Areas: 2015 Edition. 5  The Costs of Smart Growth Revisited: A 40 Year Perspective.
Definition of fossil. 1  1 : a remnant, impression, or trace of an organism of past geologic ages that has been preserved in the earth's crust â compare living fossil. 2  2a : a person whose views are outmoded : fogyb : something (such as a theory) that has become rigidly fixed.
Fossils are the remains and traces of ancient organisms. A cluster of fossil ammonites, an extinct cephalopod. fossil (latin for obtained by digging) is the preserved remains or traces of organisms (plants, animals, etc) that lived in the distant past. The convention is that a fossil must predate recorded human history. While there is no defined date, typically something must be older than 10,000 years to be considered a fossil.