The king and queen outrank all other positions in the Royal Family, followed by the princess and prince, duchess and duke, marchioness and marquees, countess and earl, viscountess and viscount and the baroness and baron. The only royal titles are "king" and "queen," while all the others are British nobility titles.
A person is considered a "royal" if they are directly related to the ruling monarch (king or queen). People with a title of nobility are not necessarily related to the monarch. Royal and noble ranks are hereditary and the hierarchy is outlined by peerage. As long as a surviving descendant of the family remains, the list will remain in existence.