a situation in which a plant, an animal, a way of life, etc. stops existing a tribe threatened with extinction/in danger of extinction The mountain gorilla is on the verge of extinction. We know of several mass extinctions in the earth's history. a campaign to save wild koalas from extinction Will technology in music drive creativity to extinction? The dormouse in Britain may face extinction if ancient woodland continues to disappear. A comet colliding with the earth may have caused the mass extinction of the dinosaurs.