lifetime
Americannoun
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lifetimes
plural
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the time that the life of someone or something continues; the term of a life.
peace within our lifetime.
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Physics. mean life.
adjective
noun
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the length of time a person or animal is alive
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( as modifier )
a lifetime supply
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the length of time that something functions, is useful, etc
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physics the average time of existence of an unstable or reactive entity, such as a nucleus, excited state, elementary particle, etc; mean life
Other Word Forms
Noun Inflected Forms
Etymology
Origin of lifetime
First recorded in 1175–1225, lifetime is from the Middle English word liftime. See life, time
Explanation
A lifetime is the entire length of time a person or other living thing is alive. After a famous actor dies, she may be fondly remembered for a lifetime of great movie roles. Things that take up most of the duration of a person's life are often described using the word lifetime, like a terrible driver's lifetime ban on holding a driver's license, or a lifetime achievement award for all of your accomplishments. You can also talk about the lifetime of an object, or the length of time it's useful, and use lifetime figuratively, to mean "a very long time."
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
At first, Cruz wondered whether the unusual bones belonged to an animal that had been sick or injured during its lifetime, which would make them an example of paleopathology.
From Science Daily ● Aug. 16, 2026
A lifetime and a revolution later, some tenets in Iranian foreign policy have stayed true.
From The Wall Street Journal ● Aug. 13, 2026
“Glaciers are leaving geologic time and are vanishing in the span of a human lifetime, which is unprecedented,” he says.
From Los Angeles Times ● Aug. 13, 2026
Over her lifetime, South Korea has witnessed the devastation of the 1950-53 war, periods of military rule and the 1990s financial crisis.
From Barron's ● Aug. 13, 2026
Columbus was determined to insist that he had seen land first because Ferdinand and Isabella of Spain had promised a lifetime pension to the first person to sight land.
From "The Invention of Science" by David Wootton
Researchers say amphibians provide a window into the past because they don’t travel far during their lifetimes and are sensitive to climate change.
From Los Angeles Times ● Aug. 7, 2026
With only a handful of lyrics, she revisits a million lifetimes replete with monumental change and insights only an artist of her caliber could convey.
From Salon ● Jul. 8, 2026
These are naturally less sensitive to tiny defects on the crystal's surface, which had shortened magnon lifetimes in previous experiments.
From Science Daily ● Jul. 2, 2026
Labor’s share of income, which is about 60% now, will almost definitely go below 50% in our lifetimes.
From The Wall Street Journal ● Jun. 28, 2026
That a few dozen hours can affect the outcome of whole lifetimes.
From "The God of Small Things" by Arundhati Roy
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
