Dragoons So called because they used to be armed with dragons, i.e. short muskets, which spouted out fire like the fabulous beast so named. The head of a dragon was wrought on the muzzle of these muskets.
The Dictionary of Phrase and Fable by Y E. Cobham Brewer
DRAGOON, n. A soldier who combines dash and steadiness in so equal measure that he makes his advances on foot and his retreats on horseback.
The Devil's Dictionary by Ambrose Bierce