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

This is Princess Cruises’ first ship to be powered by liquified natural gas, an alternative fuel that burns cleaner than diesel and reduces harmful emissions. —Condé Nast, Condé Nast Traveler, 25 Feb. 2026

Additionally, according to the Environmental Protection Agency, American oil and natural gas producers have reduced methane emissions by 42% from 2015 to 2023 while increasing oil and natural gas production by almost 50% over the same time frame. —Edward Cross, Chicago Tribune, 24 Feb. 2026

For city dwellers, ditching your car for a bike or walking just once a week makes a significant impact on personal carbon emissions. —Simmone Shah, Time, 24 Feb. 2026

While satellites provide many benefits to society, their use comes with challenges, including the growth of space debris, collisions, ground-casualty risks, optical and radio-spectrum pollution, and the alteration of Earth’s upper atmosphere through rocket emissions and reentry ablation. —Sean Williams, Harpers Magazine, 24 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