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.
Definition of fossil for English Language Learners. : 1  something (such as a leaf, skeleton, or footprint) that is from a plant or animal which lived in ancient times and that you can see in some rocks. : 2  a person whose ideas are very old-fashioned or out-of-date.