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

Starting Monday morning, one of California’s longest-running incentives for people to buy electric cars — a program that provided access to carpool lanes regardless of how many people are in a zero-emission vehicle — is coming to end. —Paul Rogers, Mercury News, 30 Nov. 2025

These are emissions that can be spotted by the JWST and MIRI. —Robert Lea, Space.com, 30 Nov. 2025

As the company explains, the development builds on earlier efforts to bring lower-emission equipment into mainstream agricultural use while still meeting the day-to-day expectations of farmers who rely on dependable power and long-duty-cycle equipment. —Bojan Stojkovski, Interesting Engineering, 30 Nov. 2025

The emissions booths used for testing motorcycles, UTVs, ATVs, and autocars are familiar. —New Atlas, 29 Nov. 2025

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