/ iˈmɪʃn; NAmE / noun
[ U ] ( formal ) the production or sending out of light, heat, gas, etc. :
the emission of carbon dioxide into the atmosphere
[ C ] gas, etc. that is sent out into the air :
The government has pledged to clean up industrial emissions.
late Middle English (in the sense emanation ): from Latin emissio(n-) , from emiss- sent out, from the verb emittere , from e- (variant of ex- ) out of + mittere send.