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.
Across the franchise’s lifetime, “Toy Story” has grossed more than $3 billion worldwide.
From Los Angeles Times • Jun. 21, 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
In drawing the moral to this experience, Graham wrote: “One lucky break, or one supremely shrewd decision — can we tell them apart? — may count for more than a lifetime of journeyman efforts.”
From MarketWatch • Jun. 17, 2026
Larry Pearlman, a Marriott rewards member since 1989, has secured lifetime platinum loyalty status with the chain after decades of traveling for work but says he is getting fewer benefits than 10 years ago.
From The Wall Street Journal • Jun. 16, 2026
We wait for approximately a year before the nurse calls us back to the consultation room, and for about a lifetime before a short woman in a big sweater dress appears through the door.
From "How to Disappear Completely" by Ali Standish
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.
