What is "lord lyon king of arms"

The Right Honourable the Lord Lyon King of Arms, the head of Lyon Court, is the most junior of the Great Officers of State in Scotland and is the Scottish official with responsibility for regulating heraldry in that country, issuing new grants of arms, and serving as the judge of the Court of the Lord Lyon, the oldest heraldic court in the world that is still in daily operation.

The historic title of the post was the High Sennachie, and he was given the title of Lord Lyon from the lion in the coat of arms of Scotland.

The post was in the early nineteenth century held by an important nobleman, the Earl of Kinnoull, whose functions were in practice carried out by the Lyon-Depute. The practice of appointing Lyon-Deputes, however, ceased in 1866.