[gas-ee-uh s, gash-uh s]


existing in the state of a gas; not solid or liquid.
pertaining to or having the characteristics of gas.
Informal. lacking firmness or solidity; uncertain; not definite.

Origin of gaseous

First recorded in 1790–1800; gas + -eous
Related formsgas·e·ous·ness, gas·e·i·ty [ga-see-i-tee] /gæˈsi ɪ ti/, nounnon·gas·e·ous, adjectivenon·gas·e·ous·ness, nounpseu·do·gas·e·ous, adjectivequa·si-gas·e·ous, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for gaseous

effervescent, aeriform

Examples from the Web for gaseous

Contemporary Examples of gaseous

Historical Examples of gaseous

British Dictionary definitions for gaseous



of, concerned with, or having the characteristics of a gas
Derived Formsgaseousness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for gaseous

1799, from gas (n.) + -ous.

Online Etymology Dictionary, © 2010 Douglas Harper

gaseous in Medicine


[găsē-əs, găshəs]


Of, relating to, or existing as a gas.
Full of or containing gas; gassy.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

gaseous in Science



One of four main states of matter, composed of molecules in constant random motion. Unlike a solid, a gas has no fixed shape and will take on the shape of the space available. Unlike a liquid, the intermolecular forces are very small; it has no fixed volume and will expand to fill the space available.
Related formsgaseous adjective (găsē-əs, găshəs)
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.