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:
Your mother will be more of a “burden” on your sister if she signs over her house during her lifetime, because she will have no place of her own to live.
From MarketWatch ● Oct. 12, 2026
Seaver said his aunt had told him she wanted to “rest in a beautiful bed of plush cotton” after spending a lifetime wearing heavy rhinestones.
From MarketWatch ● Oct. 12, 2026
He said about one in 100 people receive a diagnosis during their lifetime but research suggests the true figure could be closer to one in 50.
From BBC ● Oct. 10, 2026
It didn’t hurt that Smith gave the performance of a lifetime, putting her heart and soul into the melodramatic contradictions of the character, antagonizing Arnold one second and swooning over him the next.
From Los Angeles Times ● Oct. 7, 2026
By contrast, enslavement was intended to last a lifetime.
From "An Indigenous People’s History of the United States" by Roxanne Dunbar-Ortiz
He called himself "Sir Wicknell", a nod to the embellishment that epitomised his lifestyle - and a nickname some used for the 45-year-old who packed enough controversy into his short life to last several lifetimes.
From BBC ● Oct. 7, 2026
Scientists therefore expect stars with fewer heavy elements to produce weaker winds and lose less mass during their lifetimes.
From Science Daily ● Sep. 24, 2026
On some occasions, albeit rare but possible given extended lifetimes, an aging parent will move into a retirement community after their boomer kids.
From The Wall Street Journal ● Sep. 5, 2026
Now, 12 years and many political lifetimes later, they read as quaint and out-of-touch, like a grandfather telling his grandson to never contradict his betters.
From Salon ● Aug. 20, 2026
The discoveries of Shapley and Hubble were made within the lifetimes of many people still alive today.
From "Cosmos" by Carl Sagan
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.
