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

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Etymology

Origin of life cycle

First recorded in 1870–75

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Example Sentences

See Examples For:

life cycle

Finding these faint and relatively young remnants gives astronomers another piece of the puzzle surrounding the full life cycle of radio galaxies.

From Science Daily ● Sep. 4, 2026

"We are effectively looking at the first step in the life cycle of gold," concludes Timm.

From Science Daily ● Jul. 29, 2026

"They don't eat, they just breed and then lay eggs and die. If there's light pollution that's going to really disrupt that final stage of their life cycle," she says.

From BBC ● Jul. 27, 2026

It was expected to have a life cycle of 25 years, which it has exceeded.

From BBC ● Jul. 4, 2026

To understand how a black hole might be formed, we first need an understanding of the life cycle of a star.

From "A Brief History of Time: And Other Essays" by Stephen Hawking

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Related Words

• biological clock

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