lifetime
Americannoun
-
the time that the life of someone or something continues; the term of a life.
peace within our lifetime.
-
Physics. mean life.
adjective
noun
-
-
the length of time a person or animal is alive
-
( as modifier )
a lifetime supply
-
-
the length of time that something functions, is useful, etc
-
physics the average time of existence of an unstable or reactive entity, such as a nucleus, excited state, elementary particle, etc; mean life
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.
Underlying your desire to give money to your nephews during their lifetime are, of course, compassion and loyalty — and the fact that you can.
From MarketWatch • May 8, 2026
During his lifetime, he amassed two million acres of land across nine states, most of which he maintained for ecological preservation, including resurrecting bison populations from the brink of extinction.
From Salon • May 8, 2026
Distilled to vocals, guitar, bass, piano and drums as Perry sheds a lifetime of weight, the song ends on a single, resonant power chord — a sonic declaration of liberation.
From Los Angeles Times • May 7, 2026
It was a voyage that promised passengers the trip of a lifetime traversing some of the Atlantic's most rugged and untouched landscapes.
From BBC • May 5, 2026
Whatever he and Clara had shared during her lifetime, it was gone now.
From "Ophie's Ghosts" by Justina Ireland
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.
