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

But Green, who oversaw that recovery project, said the bog bush cricket would be more difficult to rear because it can be cannibalistic and has a longer, two-year life cycle.

From BBC • Jun. 15, 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

To investigate how the insects adapt to this dramatic transition, researchers studied deer keds at different points in their life cycle.

From Science Daily • Jun. 2, 2026

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

From Barron's • May 21, 2026

He waited with new thirst like a hunter at a chasm where the life cycle ends, where there is an end to causes, where painless eternity begins.

From "Siddhartha" by Hermann Hesse

Related Words

• biological clock