- a gaseous decomposition product of organic matter, consisting primarily of methane.
Origin of marsh gas
An Americanism dating back to 1775–85
Also called swamp gas.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for marsh gas
Many varieties of coal give off a gas known as marsh-gas or fire-damp.The Wonder Book of Knowledge
- a hydrocarbon gas largely composed of methane formed when organic material decays in the absence of air
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