emission

American  

[ih-mish-uhn] / ɪˈmɪʃ ən /

noun

emissions plural

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. Electronics. 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.

   Synonyms:

   ejaculation

6. the fluid ejected or discharged.

   Synonyms:

   ejaculate

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emission British  

/ ɪˈmɪʃən /

noun

1. the act of emitting or sending forth

2. energy, in the form of heat, light, radio waves, etc, emitted from a source

3. a substance, fluid, etc, that is emitted; discharge

4. a measure of the number of electrons emitted by a cathode or electron gun See also secondary emission thermionic emission

   at 1000°C the emission is 3 mA

5. physiol any bodily discharge, esp an involuntary release of semen during sleep

6. an issue, as of currency

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Usage

What does emission mean? An emission is something that has been emitted—released or discharged. In general, emissions consist of things like gas, liquid, heat, sound, light, and radiation. Emissions can come from natural sources or from machines. A specific example of an emission is the exhaust from cars (in the U. S., such emissions are regulated through emissions tests). This exhaust is just one form of carbon emissions—greenhouse gases from various sources that are known to contribute to global warming and climate change. Emission can also refer to an instance or the process of emitting, as in This filter is designed to reduce the emission of light. Example: Carbon dioxide emissions from volcanoes are much lower than those from cars and airplanes.

Other Word Forms

Derived Forms

• reemission
  noun
• emissive
  adjective
• nonemission
  noun

Inflected Forms

noun

• emissions
  plural

Etymology

Origin of emission

First recorded in 1600–10; from Middle French or directly from Latin ēmissiōn- (stem of ēmissiō ), equivalent to ēmiss(us), past participle of ēmittere “to send forth” ( ē- “from, out of” + mit-, stem of mittere “to send” + -tus past participle suffix) + -iōn- noun suffix; see origin at emit, e- ¹, -ion

Explanation

An emission is something that's been released or emitted into the world. Car exhaust, burps, and radio broadcasts are all examples of emissions. Technically, an emission is anything that's been released out into the open. But more often it refers to gases being released into the air, like greenhouse gasses or emissions from power plants and factories. Anytime your body emits something (sweat, drool, gas), it's also considered an emission. Be careful not to confuse this word with the closely spelled omission — that's something that's been left out.

Example Sentences

That is partly because several partners have their own energy transition schemes, like Japan's Asia Zero Emission Community.

From Barron's • Feb. 18, 2026

The Environmental Protection Agency rules announced Wednesday “certainly don’t slow down the pace at which our members are scaling up production,” said Albert Gore III, executive director of the Zero Emission Transportation Association.

From New York Times • Mar. 20, 2024

An emissions levy called the T-charge was introduced in 2017, buses had to comply with a separate Low Emission Zone by 2016 and the regulations on lorries were tightened in both 2012 and 2021.

From BBC • Mar. 11, 2024

London mayor Sadiq Khan successfully expanded the city's Ultra Low Emission Zone to include all boroughs.

From Scientific American • Oct. 22, 2023

Those of you who enjoy shooting laser beams at your friends for sport can bamboozle your opponents by crying out, “Here comes my Light Amplification by Stimulated Emission of Radiation!” just before you fire.

From "The Unseen Guest" by Maryrose Wood

Related Words

• discharge
• radiation