[ ɪ'mɪʃ(ə)n ]
■ noun the action of emitting something, especially heat, light, gas, or radiation.
↘a substance which is emitted.
Derivatives
emissive adjective
emissivity noun
Origin
ME (in the sense 'emanation'): from L. emissio(n-) , from emiss- , emittere (see emit ).