n.[U]

1. 灭绝；消灭
   Apes are in danger of extinction

   猿类正处于绝种的危险之中。

2. 熄灭；扑灭；破灭
   the extinction of one's hopes

   希望的破灭

   the extinction of a fire

   一场火的扑灭

n.

1. the state or process of being or becoming extinct.
2. Physics  reduction to zero of the intensity of light or other radiation passing through a medium, due to absorption, reflection, or scattering.