definition of
evolution

[1] #1 evolution n. [development] a process in which something passes by degrees to a different stage (especially a more advanced or mature stage); "the development of his ideas took many years"; "the evolution of Greek civilization"; "the slow development of her skill as a writer". wn

[2] #2 evolution n. [organic evolution, phylogeny, phylogenesis] (biology) the sequence of events involved in the evolutionary development of a species or taxonomic group of organisms. wn