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.
We’re probably not going to have another in our lifetime, so I really wanted to make sure we had a chance to go to some games.
From Los Angeles Times • Jun. 23, 2026
“It’s not a lifetime sentence when you choose.”
From The Wall Street Journal • Jun. 22, 2026
According to Nex, the cube has now surpassed a million lifetime units sold since its launch in December 2023 in US and Canada.
From BBC • Jun. 20, 2026
Creating SpaceX is a worthy lifetime achievement, and many have commented upon Musk becoming the world’s first trillionaire.
From Barron's • Jun. 17, 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
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.
