ev·o·lu·tion [ev-uh-loo-shuhn]
noun
1. any process of formation or growth; development: the evolution of a language; the evolution of the airplane.
2. a product of such development; something evolved: The exploration of space is the evolution of decades of research.
3. Biology . change in the gene pool of a population from generation to generation by such processes as mutation, natural selection, and genetic drift.
4. a process of gradual, peaceful, progressive change or development, as in social or economic structure or institutions.
5. a motion incomplete in itself, but combining with coordinated motions to produce a single action, as in a machine.
