The name "Roy" is the anglicised form of Ruadh. A notable bearer was the Scottish outlaw and folk hero Rob Roy (1671-1734). It is often associated with French roi "king".
Roy is also the pet form of Roibeard (the Gaelic form of Robert (disambiguation)), the short form of Royal (meaning "king" or "kingly") or the Anglicized version of the name Ruadh (meaning "red")  . It is also possible that Roy is a shortened form of another name in the Potter universe such as Royden (see Royden Poke) or Royston (see Royston Idlewind).
- Harry Potter and the Chamber of Secrets (video game) (First appearance)
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