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:
I cannot afford that, in this lifetime or any other.
From Los Angeles Times ● Jul. 13, 2026
“It has been the privilege of a lifetime to lead Brown-Forman,” Whiting said Monday.
From The Wall Street Journal ● Jul. 13, 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
I am a lifetime resident of Los Angeles and my family has always rooted for the Dodgers.
From Los Angeles Times ● Jul. 11, 2026
I do not know how long we stood there in the hallway, waiting, but it seemed like a lifetime.
From "An Elephant in the Garden" by Michael Morpurgo
Those longer lifetimes are a key reason the material became so much better at conducting heat.
From Science Daily ● Jul. 11, 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
In his letter replying to John Healey's resignation, the prime minister wrote: "The world today is more dangerous and uncertain than at any point in our lifetimes".
From BBC ● Jun. 12, 2026
We are encouraged to think that our body parts simply wear out—that they accumulate damage through our lifetimes.
From The Wall Street Journal ● Jun. 5, 2026
Such societies might live to a prosperous old age, their lifetimes measured perhaps on geological or stellar evolutionary time scales.
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.
