gaseous

adjective

gas·​eous ˈga-sē-əs  ˈga-shəs 

1

: having the form of or being gas

also : of or relating to gases

2

a

: lacking substance or solidity

b

: gassy sense 3

… trick phrases and gaseous circumlocutions …

—Edwin Newman

gaseousness noun

Synonyms of gaseous

• rhetorical
• inflated
• gassy

Examples of gaseous in a Sentence

a substance changing from a liquid to a gaseous state

a pompous professor known for his gaseous lectures that often put students to sleep

Recent Examples on the Web

Energy Dome engineers inspect the dryer system, which keeps the gaseous CO₂ in the dome at optimal dryness levels at all times. —IEEE Spectrum, 21 Dec. 2025

The fact that carbon monoxide gas has previously been detected in this system indicates these objects are rich in volatiles, substances such as hydrogen, nitrogen, oxygen and methane that easily turn gaseous at low temperatures. —Robert Lea, Space.com, 18 Dec. 2025

After blowing off its gaseous outer layers, its core contracts. —Big Think, 3 Nov. 2025

Each color in the model corresponds to different temperatures and altitudes within WASP-18 b’s gaseous atmosphere. —Eric Lagatta, USA Today, 30 Oct. 2025

Word History

First Known Use

1799, in the meaning defined at sense 1

Rhymes for gaseous

• caseous

Kids Definition

gaseous

adjective

gas·​eous ˈgas-ē-əs 

ˈgash-əs

1

: having the form of or being gas

2

: of or relating to gas

3

: lacking solidity

Medical Definition

gaseous

adjective

gas·​eous ˈgas-ē-əs  ˈgash-əs 

: having the form of or being gas

also : of or relating to gases