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

One side of the disk has an extended and brighter dust emission, which could be the result of a disturbance, possibly a vortex, that is trapping solids. —Robert Lea, Space.com, 12 Jan. 2026

And even though El Popo emanates more greenhouse gases than almost any other volcano, its emissions are still a small fraction of what humans generate in nearby Mexico City. —Arkansas Online, 11 Jan. 2026

Four seats are available on the nine-member Climate and Resiliency Commission, which monitors the city’s greenhouse gas emissions and efforts to implement the Climate Action Plan. —Luke Harold, San Diego Union-Tribune, 11 Jan. 2026

Revolution Wind, which began construction in 2023, was expected to power some three hundred and fifty thousand homes in Connecticut and Rhode Island, to reduce carbon emissions by eleven million metric tons, and to create about a thousand unionized jobs. —Margaret Talbot, New Yorker, 11 Jan. 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