Oligarchy (from Greek ὀλιγαρχία (oligarkhía); from ὀλίγος (olígos), meaning “few”, and ἄρχω (arkho), meaning “to rule or to command”) is a form of power structure in which power effectively rests with a small number of people. These people might be distinguished by nobility, wealth, family ties, education or corporate, religious or military control. Such states are often controlled by a few prominent families who typically pass their influence from one generation to the next, but inheritance is not a necessary condition for the application of this term.
Throughout history, oligarchies have often been tyrannical, relying on public obedience or oppression to exist. Aristotle pioneered the use of the term as a synonym for rule by the rich,for which another term commonly used today is plutocracy.
Plutocracy (from Greek πλοῦτος, ploutos, meaning “wealth”, and κράτος, kratos, meaning “power, dominion, rule”) or plutarchy, is a form of oligarchy and defines a society ruled or controlled by the small minority of the wealthiest citizens. The first known use of the term was in 1652. Unlike systems such as democracy, capitalism, socialism or anarchism, plutocracy is not rooted in an established political philosophy. The concept of plutocracy may be advocated by the wealthy classes of a society in an indirect or surreptitious fashion, though the term itself is almost always used in a pejorative sense.