Main Entry: emis·sion

Pronunciation: \ē-ˈmish-ən\

Function: noun

1 : an act or instance of emitting
2 a : something sent forth by emitting: as (1) : electrons discharged from a surface (2) : electromagnetic waves radiated by an antenna or a celestial body (3) : substances and especially pollutants discharged into the air (as by a smokestack or an automobile gasoline engine) b : a discharge of fluid from a living body ; especially : ejaculate—see nocturnal emission