Definition of "Extinction" :

noun: the act of extinguishing; causing to stop burning

"The extinction of the lights."

noun: a conditioning process in which the reinforcer is removed and a conditioned response becomes independent of the conditioned stimulus

noun: complete annihilation

"They think a meteor cause the extinction of the dinosaurs."

noun: the reduction of the intensity of radiation as a consequence of absorption and radiation

noun: no longer in existence

"The extinction of a species."

noun: no longer active; extinguished

"The extinction of the volcano."