emission

noun

emis·​sion ē-ˈmi-shən 

1

a

: an act or instance of emitting : emanation

b

archaic : publication

c

: a putting into circulation

2

a

: something sent forth by emitting: such as

(1)

: electromagnetic radiation from an antenna or a celestial body

(2)

usually emissions : substances discharged into the air (as by a smokestack or an automobile engine)

b

: effluvium

emissive

ē-ˈmi-siv 

adjective

Examples of emission in a Sentence

trying to reduce the emission of greenhouse gases

Recent Examples on the Web

It is used to justify regulations, such as auto emissions standards, intended to protect against threats made increasingly severe by climate change — deadly floods, extreme heat waves, catastrophic wildfires and other natural disasters in the United States and around the world. —Matthew Daly, Fortune, 10 Feb. 2026

South Coast Air Quality Management District governors have approved $30 million to help communities disproportionately impacted by air pollution replace older school buses with new, zero-emission models, the agency announced today. —City News Service, Daily News, 10 Feb. 2026

Industrial food production itself also contributes massively to climate change, from cattle ranching in the Amazon increasing greenhouse gases to food companies contributing 20 percent of global emissions merely in the transportation of food. —Annie Levin, Washington Post, 10 Feb. 2026

The silhouette arrives as Keen scales American Built production in Kentucky and pushes its sustainability targets under Ann Radil, senior director of Keen Effect, who is focused on circular design and measuring the company’s emissions trajectory. —Maggie Clancy, Footwear News, 10 Feb. 2026

Word History

First Known Use

1607, in the meaning defined at sense 1a

Phrases Containing emission

• acoustic emission
• positron-emission tomography
• re-emission
• secondary emission

Rhymes for emission

• addition
• admission
• ambition
• attrition
• audition
• clinician
• cognition
• coition
• commission
• condition
• contrition
• dentition

Kids Definition

emission

noun

emis·​sion ē-ˈmish-ən 

1

: an act or instance of emitting

2

: something emitted or discharged

emissive

ē-ˈmis-iv 

adjective

Medical Definition

emission

noun

emis·​sion ē-ˈmish-ən 

1

: an act or instance of emitting

2

a

: something sent forth by emitting: as

(1)

: electrons discharged from a surface

(2)

: electromagnetic waves radiated by an antenna or a celestial body

(3)

: substances and especially pollutants discharged into the air (as by a smokestack or an automobile gasoline engine)

b

: a discharge of fluid from a living body

especially : ejaculate see nocturnal emission