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

Their analysis found that glacier extinction will peak around mid-century, with the exact timing and extent dependent on the level of global warming. —Laura Paddison, CNN Money, 15 Dec. 2025

Humans put shark species at risk of extinction Sharks have had a rough ride since the 1970s, when overfishing, habitat loss and international trade in fins, oil and other body parts of these enigmatic sea dwellers began to affect their sensitive populations. —Gareth J. Fraser, The Conversation, 12 Dec. 2025

Gone are the selfies taken before or after an escalator ride, gone is the spotlight that prompted travelers to toss in coins or dollars at its feet for good luck, or to ward off our own extinction. —John Shumway, CBS News, 10 Dec. 2025

From Shinichiro Watanabe, best known as the creator of Cowboy Bebop, comes Lazarus, a globe-trotting thriller involving a race against the clock to save humanity from extinction. —Kambole Campbell, Vulture, 9 Dec. 2025

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