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

Launched at the 2021 climate talks in Glasgow, the initiative aims to reduce methane emissions by at least 30% from 2020 levels by 2030. — Arkansas Online, 12 Nov. 2026

Ammann developed the machine in response to demand for quieter equipment that can work without direct exhaust emissions while maintaining the precision and steady movement needed for a consistent surface. — Atharva Gosavi, Interesting Engineering, 11 Nov. 2026

The oil extraction process in this region generates a lot of greenhouse gas emissions, says Paasha Mahdavi, a political science professor at UC Santa Barbara who studies the oil industry. — Julia Simon, NPR, 11 Nov. 2026

In its August 28, 2025 letter, the agency instructed the port to remove language treating those movements as automatically exempt from emissions requirements. — Harry T Angell, Oc Register, 11 Nov. 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