emission (n.) Look up emission at Dictionary.com
early 15c., "something sent forth," from Middle French émission (14c.) and directly from Latin emissionem (nominative emissio) "a sending out, a projecting, hurling, letting go, releasing," noun of action from past participle stem of emittere "send out" (see emit). Meaning "a giving off or emitting" is from 1610s.