Other forms: emissions
An emission is something sent out into the air — usually the gases from an engine, a factory or a power station. Carbon emissions, emission standards, cut emissions by half.
It is almost always plural in this sense, and emissions on its own now means greenhouse gases without anything else being said. That is a recent narrowing and it is worth knowing, because emission in the singular is a technical word for any sending-out — the emission of light, the emission of a sound. Note net zero and low-emission, both fixed compounds, and that emit is the verb: a factory emits, it does not emission.
1nounemissionGases sent into the air by vehicles, factories or power stations.
“Emissions have fallen by a fifth since 2010.”
2nounsendingThe sending out of light, heat, sound or a substance.
“The emission of light happens at a particular wavelength.”
emission is something sent out.
Also accepted in games: emissions
Latin emissio is a sending out, from emittere — ex-, out, plus mittere, to send, the same verb behind mission, transmit and permit. An emission is anything sent out, and the modern narrowing to exhaust gases is only a century old.
Latin
ēmissiō
Middle French
émission
English, today
emission
Built from
Borrowed from Middle French émission, from Latin ēmissiō. First attested in 1607. From Middle French émission, from Latin ēmissiō (“sending forth”), from ēmittō (“send out”), from ex (“from, out of”) + mittō (“send”).
Etymology from Wiktionary, CC BY-SA