Kingsman is a rank in the British Army equivalent to Private. Historically, it could be applied to any man serving in the British Army from the late 17th century. Today it is only used by the Duke of Lancaster's Regiment, which inherited it from the King's Regiment.
Kingsman is also a family name, believed to have derived from certain farmers in Loddington and Broughton, Northamptonshire, England who in the Middle Ages held their land directly from the king, without any feudal lord in between. Descendant families include Kingman, Kinsman and Kinman.
The word "kingsman" is also a slang term for the large kerchief worn by costermongers.