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:
Studies suggest that approximately 5% to 10% of people develop carpal tunnel syndrome during their lifetime, and the number of cases is increasing.
From Science Daily ● Oct. 22, 2026
It has estimated that Jackdaw could produce 35.8 million tonnes of carbon over its lifetime, the equivalent of 90% of Scotland's emissions for 2023.
From BBC ● Oct. 21, 2026
Last season, when the Chargers swept the Chiefs, feels like a lifetime ago.
From Los Angeles Times ● Oct. 17, 2026
“I’d say the advent of this new technology is probably the most consequential change to the U.S. and the global economy in my lifetime at this point,” Federal Reserve Chairman Kevin Warsh said Friday.
From The Wall Street Journal ● Oct. 16, 2026
Below are some materials to help you create a vision of your “professional” self that will serve you throughout your career and lifetime.
From "Music and the Child" by Natalie Sarrazin
In 2015, Zuckerberg and his wife, Dr. Priscilla Chan, pledged to give away 99% of his Facebook shares over their lifetimes when they celebrated the birth of their first daughter.
From Los Angeles Times ● Oct. 22, 2026
We should be careful about assuming today’s data-center demand projections will hold over these investments’ lifetimes.
From The Wall Street Journal ● Sep. 25, 2026
In a 2016 Pew Research Center survey, 76% of Americans named 9/11 as one of the 10 most consequential events of their lifetimes.
From Salon ● Sep. 8, 2026
The boss of the biggest UK-headquartered tech firm has said that artifical intelligence will find a cure for cancer that humans cannot in our lifetimes.
From BBC ● Sep. 7, 2026
The great majority have lifetimes of billions or more years in which they are shining stably, providing a suitable energy source for the origin and evolution of life on nearby planets.
From "Cosmos" by Carl Sagan
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Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
