extinction

noun

ex·​tinc·​tion ik-ˈstiŋ(k)-shən 

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.

Synonyms of extinction

• destruction
• devastation
• havoc
• loss
• demolition
• extermination

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

This year, with a bumper crop of the strange parrot’s favorite berries prompting a rare enthusiasm for mating, those working to save the birds hope for a record number of chicks in February, which would move the kakapo closer to defying what was not long ago believed to be certain extinction. —Charlotte Graham-McLay, Los Angeles Times, 24 Feb. 2026

In his scenario, this is what finally pushes the technology down the path toward either utopia or human extinction, but in the real world, getting the machines to act by themselves is proving surprisingly difficult. —Sam Kriss, Harpers Magazine, 24 Feb. 2026

Cadwallader sees this shift as an expansion of SEO, not its extinction. —Lily Mae Lazarus, Fortune, 24 Feb. 2026

Quick recovery after extinction Interestingly, the fossil identification suggests that even in the immediate, volatile aftermath of a global catastrophe, these creatures were not isolated. —Mrigakshi Dixit, Interesting Engineering, 23 Feb. 2026

Word History

First Known Use

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

Phrases Containing extinction

• extinction coefficient
• mass extinction
• mass extinction event
• self-extinction

Rhymes for extinction

• distinction
• contradistinction
• tinction

Kids Definition

extinction

noun

ex·​tinc·​tion ik-ˈstiŋ(k)-shən 

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 

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