[ih-mish-uh n]
See more synonyms for emission on Thesaurus.com
  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.
  6. the fluid ejected or discharged.

Origin of emission

1600–10; (< Middle French) < Latin ēmissiōn- (stem of ēmissiō), equivalent to ēmiss(us), past participle of ēmittere to emit (ē- e-1 + mit- send + -tus past participle suffix) + -iōn- -ion
Related formsnon·e·mis·sion, nounre·e·mis·sion, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for emission

Contemporary Examples of emission

  • The DEP has authority only over manufacturing or emission sites, not mere storage sites, as this one is.

    The Daily Beast logo
    The Charleston Water Saga

    Michael Tomasky

    January 14, 2014

  • As in: At current emission levels, we will suffer Total Weather Apocalypse by 2050.

    The Daily Beast logo
    Great Weekend Reads

    The Daily Beast

    February 12, 2011

  • Emission reductions from recycling are not massive, but they are still significant.

Historical Examples of emission

British Dictionary definitions for emission


  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 gunat 1000°C the emission is 3 mA See also secondary emission, thermionic emission
  5. physiol any bodily discharge, esp an involuntary release of semen during sleep
  6. an issue, as of currency
Derived Formsemissive, adjective

Word Origin for emission

C17: from Latin ēmissiō, from ēmittere to send forth, emit
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for emission

early 15c., "something sent forth," from Middle French émission (14c.) and directly from Latin emissionem (nominative emissio) "a sending out, projecting, hurling, letting go, releasing," from past participle stem of emittere "send out" (see emit). Meaning "a giving off or emitting" is from 1610s.

Online Etymology Dictionary, © 2010 Douglas Harper

emission in Medicine


  1. A discharge of fluid from a living body, usually a seminal discharge.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.