Meaning of emission

e•mis•sion

1. an act or instance of emitting: the emission of poisonous fumes.
2. something that is emitted; discharge; emanation.
3. an act or instance of issuing, as paper money.
4. a measure of the number of electrons emitted by the heated filament or cathode of a vacuum tube.
5. an ejection or discharge of semen or other fluid from the body.
6. the fluid ejected or discharged.