Royal dukedoms in the United Kingdom
In the British peerage, a royal duke is a member of the British royal family, entitled to the titular dignity of prince and the style of "His Royal Highness" who holds a dukedom. Dukedoms are the highest titles in the British roll of peerage and the holders of these particular dukedoms are Princes of the Blood Royal. The holders of the dukedoms are royal not the titles themselves. They are titles created and bestowed on legitimate sons and male-line grandsons of the British monarch, usually upon reaching their majority or marriage. The titles can be inherited but cease to be called "royal" once they pass beyond the grandsons of a monarch. As with any peerage, once the title becomes extinct, it may subsequently be recreated by the reigning monarch at any time.
British nobility
Descendants in the male-line of peers and children of women who are peeresses in their own right, as well as baronets, knights, dames and certain other persons who bear no peerage titles belong to the gentry, deemed members of the non-peerage nobility below whom they rank. The Scottish feudal barony, an official title of nobility in the United Kingdom, is addressed as "The Baron of X". The untitled nobility consists of all those who bear formally matriculated, or recorded, armorial bearings. Other than their designation, such as Gentleman or Esquire, they enjoy only the privilege of a position in the formal orders of precedence in the United Kingdom. The largest portion of the British aristocracy have historically been the landed gentry, made up of baronets and the non-titled armigerous landowners whose families hailed from the mediaeval feudal class (referred to as gentlemen due to their income solely deriving from land ownership).