extinction

noun

ex·​tinc·​tion ik-ˈstiŋ(k)-shən How to pronounce extinction (audio)
plural extinctions
1
a
: the act of making extinct or causing to be extinguished
gradual extinction of the national debt
b
: the condition or fact of being extinct
also : the process of becoming extinct
attempting to save a species from extinction
… at least 17 species of the island's largest mammals, birds, and reptiles were lost in a wave of extinctions that occurred about 1,000 years ago. Pamela S. Cubberly
Now, more than 40 percent of the world's 7,000 or so languages are thought to be at risk of extinction, some with just a handful of elderly native speakers left. Benjamin Plackett
see also mass extinction
2
: the process of eliminating or reducing a conditioned (see conditioned sense 2) response by not reinforcing it
When a rat in a Skinner box presses a lever, a tone sounds momentarily, followed shortly by delivery of food. … After the animal has been conditioned in this way, the experimenter begins extinction, so that when the rat presses the lever neither the tone nor the food appears.Rita L. Atkinson et al.

Examples of extinction in a Sentence

the extinction of all life in the region the extinction of many old traditions Mass extinctions of prehistoric animals are known to have occurred.
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.
As the Earth's climate cooled and the oceans' ecosystems changed, Megalodon may have struggled to find sufficient food, leading to its extinction. Scott Travers, Forbes.com, 9 Apr. 2025 Game of Thrones author George R.R. Martin had an emotional meeting with a pair of dire wolves, but many fans have shared the same unimpressed response, not quite able to believe a species was brought back from extinction before Martin finished the next book in his A Song of Ice and Fire series. Raja Krishnamoorthi, MSNBC Newsweek, 9 Apr. 2025 The Late Devonian extinction, nearly four hundred million years ago, annihilated the jawless fish. D. T. Max, New Yorker, 7 Apr. 2025 In the mid-1980s, the species was officially declared extinct in the wild, the final classification before complete extinction, including in captivity. Lauren Liebhaber, Miami Herald, 28 Mar. 2025 See All Example Sentences for extinction

Word History

First Known Use

15th century, in the meaning defined at sense 1a

Time Traveler
The first known use of extinction was in the 15th century

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Cite this Entry

“Extinction.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/extinction. Accessed 16 Apr. 2025.

Kids Definition

extinction

noun
ex·​tinc·​tion ik-ˈstiŋ(k)-shən How to pronounce extinction (audio)
1
: an act of extinguishing or an instance of being extinguished
2
a
: the state of being extinct
b
: the process of becoming extinct
3
: the process of eliminating or reducing a conditioned response by not providing the stimulus with which it has become associated by conditioning

Medical Definition

extinction

noun
ex·​tinc·​tion ik-ˈstiŋ(k)-shən How to pronounce extinction (audio)
1
: the process of becoming extinct
the extinction of a species
also : the condition or fact of being extinct
2
: the process of eliminating or reducing a conditioned response by not reinforcing it

More from Merriam-Webster on extinction

Last Updated: - Updated example sentences
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