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.
Long genetic and social isolation in Neanderthals before their extinction Smithsonian National Museum of Natural History. Sara Novak, Discover Magazine, 18 Apr. 2025 Research on the Australian thylacine (Tasmanian tiger), driven to extinction less than a century ago, is ahead of schedule. Mike Snider, USA Today, 16 Apr. 2025 Once the end-Triassic extinction struck, no non-crocodylomorph pseudosuchians survived despite being so dominant. Laura Baisas, Popular Science, 16 Apr. 2025 In the 19th and 20th centuries, they were hunted nearly to extinction after the seal population was hit severely and hunters turned to the king penguins as a new source of oil, according to the program. Irene Wright, Miami Herald, 15 Apr. 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 29 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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