Until the 19th century, it was taken for granted that a legitimate function of a monarch was to aggrandize his dynasty: that is, to increase the territory, wealth, and power of his family members. The longest-surviving dynasty in the world is the Imperial House of Japan, the Yamato dynasty, whose reign is traditionally dated to 660 BC.
In South Africa's Limpopo Province, Balobedu determined descent matrilineally, while rulers have at other times adopted the name of their mother's dynasty when coming into her inheritance. Less frequently, a monarchy has alternated or been rotated, in a multidynastic (or polydynastic) system – that is, the most senior living members of parallel dynasties, at any point in time, constitute the line of succession.
The word "dynasty" is sometimes used informally for people who are not rulers but are, for example, members of a family with influence and power in other areas, such as a series of successive owners of a major company. It is also extended to unrelated people, such as major poets of the same school or various rosters of a single sports team.
The word "dynasty" derives from Latin dynastia, which comes from Greekdynastéia (δυναστεία), where it referred to "power", "dominion", and "rule" itself. It was the abstract noun of dynástēs (δυνάστης), the agent noun of dynamis (δύναμις), "power" or "ability", from dýnamai (δύναμαι), "to be able".