Methane, especially as generated by decaying matter in marshes.
More example sentences
- Methane is often called marsh gas because it forms in swamps and marshes from the underwater decomposition of plant and animal material.
- Occasionally a hiss of marsh gas would sound, like a snake's venomous warning.
- The smell of sulfurous marsh gas drifted over the stockade to mix with the smell of disease and spoiling food.
Definition of marsh gas in:
- The US English dictionary