royal house

A Royal House or royal dynasty is a familial designation, or family name of sorts, used by royalty. It generally represents the members of a family in various senior and junior or cadet branches, who are loosely related but not necessarily of the same immediate kin. Unlike most westerners, many of the world's royal families do not have family names, and those that have adopted them rarely use them. They are referred to instead by their titles, often related to an area ruled or once ruled by that family. The name of a Royal House is not a surname; it is just a convenient way of dynastic identification of individuals.
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Noun
1. royal persons collectively; "the wedding was attended by royalty"
(synonym) royalty, royal family, royal line
(hypernym) house
(hyponym) Hanover, House of Hanover, Hanoverian line
(member-meronym) Highness