lifespan

noun

life·​span ˈlīf-ˌspan How to pronounce lifespan (audio)
variants or less commonly life span
plural lifespans also life-spans
Synonyms of lifespannext
1
: the average length of life of a kind of organism or of a material object especially in a particular environment or under specified circumstances
2
: the duration of existence of an individual

Examples of lifespan in a Sentence

the average lifespan of house cats increase the human lifespan
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The excellent active noise-cancellation feature uses batteries with an 80-hour lifespan. Bestreviews, Mercury News, 15 Apr. 2026 Normal operations still generate heat, and high temperatures can degrade performance and reduce lifespan. New Atlas, 15 Apr. 2026 The original Wylfa power station, once Britain’s oldest nuclear plant, concluded 44 years of operations in 2015, having reached the end of its natural lifespan. Mrigakshi Dixit, Interesting Engineering, 14 Apr. 2026 Even small hail impacts can weaken protective layers, shorten a roof’s lifespan, and create vulnerabilities that may not surface until months later. Ethan Stone, USA Today, 14 Apr. 2026 The average lifespan of this diminutive Peruvian mammal, in captivity, is 25 years. Baz Bamigboye, Deadline, 13 Apr. 2026 That means Fatou has nearly doubled the lifespan of her wild counterparts — a fact that might spark big questions from curious kids about how animals age and why care makes such a difference. Hanna Wickes, Miami Herald, 13 Apr. 2026 Five Generations and Counting Fatou’s legacy extends well beyond her own remarkable lifespan. Hanna Wickes, Charlotte Observer, 13 Apr. 2026 Today, these lovable lap dogs have a lifespan of 12 to 15 years. Katelyn Chef, Martha Stewart, 12 Apr. 2026

Word History

First Known Use

1831, in the meaning defined at sense 2

Time Traveler
The first known use of lifespan was in 1831

Browse Nearby Words

Cite this Entry

“Lifespan.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lifespan. Accessed 17 Apr. 2026.

Kids Definition

life span

noun
: the average length of life of a living thing or of the persistence of a material object under specified circumstances or in a particular environment

Medical Definition

lifespan

noun
variants also life span
1
: the duration of existence of an individual
2
: the average length of life of a kind of organism or of a material object especially in a particular environment or under specified circumstances
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