lifetime
Americannoun
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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:
“It has been the privilege of a lifetime to lead Brown-Forman,” Whiting said Monday.
From The Wall Street Journal ● Jul. 13, 2026
I cannot afford that, in this lifetime or any other.
From Los Angeles Times ● Jul. 13, 2026
For Amy, the South Africa internship was more than just a once in a lifetime trip - but a chance to get hands-on experience in her dream job.
From BBC ● Jul. 11, 2026
Although most women experience one or more pregnancies during their lifetime, scientists are only beginning to understand how pregnancy influences the brain over the long term.
From Science Daily ● Jul. 11, 2026
This period of control may last a lifetime, even for those convicted of extremely minor, nonviolent offenses, but the vast majority of those swept into the system are eventually released.
From "The New Jim Crow" by Michelle Alexander
Perhaps the most surprising discovery was identifying what now limits magnon lifetimes.
From Science Daily ● Jul. 2, 2026
By increasing magnon lifetimes to as much as 18 microseconds, the researchers turned these once fleeting signals into long-lasting carriers of quantum information.
From Science Daily ● Jul. 2, 2026
However, among graduate men with low prior attainment, around four in 10 can expect to be worse-off financially over their lifetimes than if they had not gone to university.
From BBC ● Jun. 25, 2026
By the time I went to college, I had consumed more candy than most people do in five lifetimes.
From The Wall Street Journal ● Jun. 9, 2026
“I will live a thousand lifetimes and it will still be the most embarrassing thing that’s ever happened to me.”
From "The Sun Is Also a Star" by Nicola Yoon
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.
