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.
Lord
The upper house of the Parliament of the United Kingdom is the House of Lords, which is an abbreviation of the full title, The Right Honourable the Lords Spiritual and Temporal in Parliament Assembled. The Lords Temporal are the people who are entitled to receive writs of summons to attend the House of Lords in right of a peerage. The Lords Spiritual are the Archbishops of Canterbury and York, the Bishops of London, Winchester and Durham, and the twenty-one longest-serving bishops of the Church of England from among the other bishops, who are all entitled to receive writs of summons in right of their bishoprics or archbishoprics.