Busby

A tall fur hat worn by certain military units, especially the British Guards, typically made of bearskin.

Named after Dr. Richard Busby (1606-1695), headmaster of Westminster School, who wore a similar style of large wig that resembled the later military fur hat. The military adopted this style in the 18th century, and the name stuck despite the hat being quite different from Busby's academic headpiece. It's one of the few military items named after a schoolteacher rather than a general or battle.