Aristocracy, ar uh STOK ruh see, is a high social class that often used to include the government leaders of a state or nation. Its members claim to be, or are considered by others to be, superior to other people in the society because of family ties, social rank, wealth, or ability. Historically, the word aristocracy referred to a form of government controlled by a few wealthy or socially prominent citizens. The word comes from the Greek term meaning rule by the best.