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

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

See Examples For:

emission emissions

Yet even if the entire world managed dramatic emission cuts, the fire would still burn 5.5% more intensely in 2050.

From The Wall Street Journal ● Aug. 12, 2026

SpaceXAI, which did not respond to a request for comment, said in a statement that it is working to make sure that its mobile turbines are "equipped with advanced emission control technologies."

From Barron's ● Aug. 11, 2026

“The conditions encourage speed. Removing the source of the odors is the primary objective here. However, that speed should not come at the detriment of the emission of odors or public health.”

From Los Angeles Times ● Aug. 6, 2026

Third, Chandra detected only very weak diffuse X-ray emission.

From Science Daily ● Aug. 2, 2026

Of course, if a black hole as close as Pluto were to reach the end of its life and blow up, it would be easy to detect the final burst of emission.

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

It was higher than 20.7 million metric tons of emissions from fires over the same period in 2015, which was a strong El Nino year.

From Barron's ● Sep. 5, 2026

Fires in the archipelago have released more than 23 million metric tons of carbon emissions between August 28 and September 3, according to CAMS' Fire Emission Watch portal.

From Barron's ● Sep. 5, 2026

Nepal is one of the most vulnerable countries to the climate crisis, even though it is one of the lowest emitters of global greenhouse emissions.

From BBC ● Sep. 4, 2026

If it fails, California will have to find new ways to eliminate emissions from other sectors, according to Lindsay Buckley, a spokesperson for the California Air Resources Board.

From Los Angeles Times ● Sep. 4, 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

Related Words

• discharge
• radiation