Definitions of extinction:

• noun:   the act of extinguishing; causing to stop burning

  Example: "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

  Example: "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

  Example: "The extinction of a species"

• noun:   no longer active; extinguished

  Example: "The extinction of the volcano"