Definition - What does Evolution mean?
Evolution is a term used to describe any process of gradual development or steady growth from one thing to something greater or more complex. In biology, it is the term given to the theory that all species descend from one common ancestor and have developed into what they are today through natural selection over a long period of time. This process is theorized to have happened over millions of years.
Safeopedia explains Evolution
The word evolution is the name given to the theory and also to the process of natural selection that is theorized to have happened over millions of years. It is considered by many to be a proven theory, and adaptations within a species are often supplied as proof for the theory of evolution. The process of one species changing into another has never been observed or proved definitively.