Busby is the English name for the Hungarian prémes csákó or kucsma, a military head-dress made of fur, worn by Hungarian hussars. In its original Hungarian form the busby was a cylindrical fur cap, having a bag of colored cloth hanging from the top. The end of this bag was attached to the right shoulder as a defense against sabre cuts. In Great Britain busbies are of two kinds: (a) the hussar busby, cylindrical in shape, with a bag; this is worn by hussars and the Royal Horse Artillery; (b) the rifle busby, a folding cap of astrachan (curly lambswool) formerly worn by rifle regiments, in shape somewhat resembling a Glengarry but taller. Both have straight plumes in the front of the headdress.
The popularity of this military headdress in its hussar form reached a height in the years immediately before World War I (1914-18). It was widely worn in the British (hussars, yeomanry, and horse artillery), German (hussars), Russian (hussars), Dutch (cavalry and artillery), Belgian (Guides and field artillery), Bulgarian (Life Guards), Romanian (cavalry), Austro-Hungarian (Hungarian generals) Serbian (Royal Guards), Spanish (hussars) and Italian (light cavalry) armies.
Possibly the name's original sense of a 'busby wig' came from association with Dr Richard Busby, headmaster of Westminster School in the late 1600s; it is also derived from buzz, in the phrase ~ buzz wig.
The busby should not be mistaken for the much taller bearskin cap, worn most notably by the five regiments of Foot Guards of the Household Division (Grenadier, Coldstream, Scots, Irish and Welsh Guards). The 1911 edition of the Encyclopaedia Britannica notes that the word "busby" was at that time used colloquially to denote the tall bear and racoonskin "caps" worn by foot-guards and fusiliers and the feather bonnets of highland infantry. This practice has now fallen into disuse.