/ɪk'stɪŋkʃn; ɪk`stɪŋkʃən/
n [U]
1 action of making extinct; state of being extinct 灭绝; 绝种
*We may live to see the extinction of the whale. 人类或许能亲眼见到鲸的灭绝.
* a tribe threatened by/with extinction 受到绝种威胁的部落.
2 (fml 文) act of extinguishing 熄灭
*the extinction of a fire, a political movement, youthful hopes 火的熄灭、政治运动的平息、青年人希望的幻灭.

n[U]
when a particular type of animal or plant stops existing
　species in danger of extinction
on the verge/edge/brink of extinction
(=nearly extinct)
　The breed was on the verge of extinction.
　They were hunted almost to extinction .
　Conservationists are trying to save the whale from extinction .
face extinction/be threatened with extinction
　Many endangered species now face extinction.
when a type of person, custom, skill etc stops existing
　Their traditional way of life seems doomed to extinction.