life cycle

American  

noun

1. Biology. 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.

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life cycle British  

noun

1. the series of changes occurring in an animal or plant between one development stage and the identical stage in the next generation

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life cycle Scientific  

1. The series of changes in the growth and development of an organism from its beginning as an independent life form to its mature state in which offspring are produced. In simple organisms, such as bacteria, the life cycle begins when an organism is produced by fission and ends when that organism in turn divides into two new ones. In organisms that reproduce sexually, the life cycle may be thought of as beginning with the fusion of reproductive cells to form a new organism. The cycle ends when that organism produces its own reproductive cells, which then begin the cycle again by undergoing fusion with other reproductive cells. The life cycles of plants, algae, and many protists often involve an alternation between a generation of organisms that reproduces sexually and another that reproduces asexually.

2. See more at alternation of generations

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Etymology

Origin of life cycle

First recorded in 1870–75

Example Sentences

“This life cycle analysis now looks at all different environmental indicators on this — the chemical usage, the water usage, and the end-of-life impacts on that side of things.”

From Los Angeles Times • Jun. 5, 2026

An IPO used to mark the beginning of an investible company’s life cycle.

From Barron's • May 21, 2026

"It is amazing to see how interested people become once they hear about their incredible life cycle," she said.

From BBC • May 7, 2026

"These new findings help us better understand the life cycle of the tectonic plates that shape the Earth."

From Science Daily • Apr. 29, 2026

The Coho salmon has a three-year life cycle and the runs are composed almost entirely of fish of a single age group.

From "Silent Spring" by Rachel Carson

Related Words

• biological clock