The Collaborative International Dictionary
Buckhound \Buck"hound`\, n. A hound for hunting deer.
Master of the buckhounds, an officer in the royal household. [Eng.]
Wikipedia
The Master of the Buckhounds was an officer in the Master of the Horse's department of the British Royal Household. The holder was also His/Her Majesty's Representative at Ascot. It was a political office, so the holder, who was always a nobleman, changed with every change of government. The office was abolished by the Civil List Act 1901. (A buckhound is smaller than a staghound and used for coursing the smaller breeds of deer, especially fallow deer.)
Usage examples of "master of the buckhounds".
It was not everyone who had a First Lord of the Treasury, Lord Chief Justice, Commander in Chief, Great Scientist, Master of the Buckhounds, Groom of the Backstairs and the Lord Mayor to accompany them.