A dynasty (UK: i/, US: i/) is a sequence of rulers from the same family, usually in the context of a feudal or monarchical system, but sometimes also appearing in electiverepublics. Alternative terms for "dynasty" may include "house", "family" and "clan", among others. The longest-surviving dynasty in the world is the Imperial House of Japan, otherwise known as the Yamato dynasty, whose reign is traditionally dated to 660 BC.
Historiansperiodize the histories of numerous nations and civilizations, such as Ancient Egypt (3100–30 BC) and Imperial China (221 BC–AD 1912), using a framework of successive dynasties. As such, the term "dynasty" may be used to delimit the era during which a family reigned, and also to describe events, trends and artifacts of that period (for example, "a Ming-dynasty vase"). The word "dynasty" itself is often dropped from such adjectival references (e.g., "a Ming vase").
Until the 19th century, it was taken for granted that a legitimate function of a monarch was to aggrandize his dynasty: that is, to expand the wealth and power of his family members.
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 Latindynastia, 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".