Firedamp

Part of speech: noun

Definitions

1. A mixture of methane and air that accumulates in coal mines and is highly explosive when ignited
2. Methane gas that collects in coal seams and forms a dangerous explosive hazard in underground mining operations
3. The inflammable gas composed primarily of methane that builds up in coal mines and poses a severe risk of explosion

Etymology: Miners who worked in coal seams once had to contend with a gas that could explode at the lamp, and the word for it puts two plain English words together in a way that surprises most readers. "Fire" is obvious, but "damp" does not mean moist here. In older German, and in modern Dutch and Danish, "damp" means steam or vapour, and the word was borrowed into English with that sense. So firedamp is literally a vapour that catches fire: the gas, mostly methane, that collects in coal mines and ignites when it meets a flame. The compound follows a pattern English miners used for other underground hazards. Blackdamp, the oxygen-poor gas that suffocates rather than burns, took its name from the same "damp" vapour sense, which shows how the miners' vocabulary treated the word as a general term for any gas in the workings. Together the two terms gave the trade a practical split between what burns and what kills.

Synonyms: methane