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

• nonemission
  noun
• reemission
  noun
• emissive
  adjective

Inflected Forms

Nouns

• emissions
  plural

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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

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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

See Examples For:

emission emissions

France and Germany have backed a further scaling down of EU emission rules for cars as part of a long-negotiated deal on the automotive industry struck Thursday, diplomatic sources confirmed to AFP.

From Barron's ● Oct. 15, 2026

Germany wanted less stringent carbon emission targets for carmakers and a broad interpretation of "made in Europe" to include key non-EU trade partners.

From Barron's ● Oct. 15, 2026

"One plausible explanation is that the merger produced a rapidly rotating, highly magnetized neutron star -- known as a magnetar -- that powered the extended X-ray emission and continued energy injection," said Yin.

From Science Daily ● Oct. 8, 2026

European Commission President Ursula von der Leyen said exporters will get an extra year to comply with incoming EU methane emission rules.

From The Wall Street Journal ● Oct. 6, 2026

So as the black hole loses mass, its temperature and rate of emission increase, so it loses mass more quickly.

From "A Brief History of Time: And Other Essays" by Stephen Hawking

"Gas turbines appear in the planning documents because they represent the worst case for emissions and noise, so assessing them tests the upper limit of any impact."

From BBC ● Oct. 16, 2026

The member of the Cardiff Council cabinet and Llanrumney ward councillor said in a letter it was "hard to reconcile" the centre's emissions "with Cardiff's climate emergency declaration and Planning Policy Wales".

From BBC ● Oct. 16, 2026

An initiative co-founded by McCormick, Climate TRACE, harnesses the technology to track emissions around the planet and build an inventory of the pollutants.

From Barron's ● Oct. 15, 2026

Many experts, from Microsoft to McKinsey, have pointed to materials-science breakthroughs as a key way in which AI could help cut emissions.

From The Wall Street Journal ● Oct. 15, 2026

They had bombarded dozens of elements with deuterons and assiduously tracked emissions of alpha particles during the bombardments; but the continued emission of electrons or positrons after the bombardments ended had escaped their notice.

From "Big Science" by Michael Hiltzik

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Related Words

• discharge
• radiation

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