1. Biol.the continuous sequence of changes undergone by an organism from one primary form, as a gamete, to the development of the same form again.
2. a series of stages, as childhood and middle age, that characterize the course of existence of an individual, group, or culture.
3. any similar series of stages: the life cycle of a manufactured product.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.