Definition of: extinction

(ik·stingk′shən) noun
1. The act of extinguishing or state of being extinguished; extinguishment.
2. A putting an end to something; a destroying; complete destruction; annihilation.
3. A quenching or slaking, as of quicklime with water.
4. Physics A diminution in the intensity of radiation due to absorption by or scattering in the medium; also, the stopping of incident X–rays by the outer layers of atoms in a crystal.