These days, you're most likely to hear dragoon used as a verb meaning "force someone to do something," like the way your best friend dragooned you into volunteering for the prom committee. Long ago, dragoons were soldiers who rode horses into battle and were trained to fight either on foot or on horseback.
It's easy to mistake dragoon for dragon, and it might not be surprising to know the two words are related. Dragoons were named for one of the weapons they frequently carried, powerful muskets said to "breathe fire," known as dragons. European armies commonly included dragoon regiments from the late 17th century until the early 20th century, and dragoons also fought in the Revolutionary War.