life cycle

American  

noun

• life cycles
  plural

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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Other Word Forms

Noun Inflected Forms

• life cycles
  plural

Etymology

Origin of life cycle

First recorded in 1870–75

Example Sentences

See Examples For:

life cycle

"It hasn't been able to adapt its life cycle away from this need from a certain temperature on the ground. The cutting of the bracken is essential."

From BBC ● Jul. 10, 2026

Each was an intricate interpretation of an insect at a specific stage of its life cycle.

From The Wall Street Journal ● Jul. 5, 2026

Their hydropower plants, which have a long life cycle and generate high free cash flow, are underappreciated by the market, they write.

From The Wall Street Journal ● Jun. 22, 2026

“We want to look at the full life cycle … not only thinking from the cradle to the grave, but from the point where the raw materials are extracted at the beginning,” Stanton says.

From Los Angeles Times ● Jun. 5, 2026

And Siddhartha’s soul returned, died, decayed, turned into dust, experienced the troubled course of the life cycle.

From "Siddhartha" by Hermann Hesse

Related Words

• biological clock