monarchy

n. kingdom; rule by a hereditary sovereign; form of government with a monarch at its head; monarchical state

A Monarchy, from the Greek μονος, "one", and αρχειν, "to rule", is a form of government in which a monarch, usually a single person, is the head of state. In most monarchies, the monarch holds control and their position for life (in a few republics, the head of state, often styled president, might remain in office for life, but most are elected for a term of office, after which he or she must step down). There are currently 31 monarchs reigning over 45 extant sovereign monarchies in the world; the disconnect in numbers between monarchs and countries is explained by the fact that the sixteen Commonwealth realms - vast geographic areas including the trans-continental realms of Canada and Australia - are separately debated over in personal union by one Sovereign, and one other monarchy, Andorra, by two non-resident foreign (French and Spanish) co-monarchs.
See more at Wikipedia.org...

Noun
1. an autocracy governed by a monarch who usually inherits the authority
(hypernym) autocracy, autarchy
(hyponym) parliamentary monarchy

(n.)
The territory ruled over by a monarch; a kingdom.
  

(n.)
A system of government in which the chief ruler is a monarch.
  

(n.)
A state or government in which the supreme power is lodged in the hands of a monarch.
  

A form of rule in which there is a single head of state, a monarch, with the title of King (or Queen) or its equivalent; in which the monarch holds his or her office for life; in which the position of monarch normally descends by rules of heredity only to members of a specific royal family; and where the monarch is popularly believed to be possessed of a religious or similar symbolic significance for the state and its institutions that legitimate his or her privileges. When the monarch rules with full or nearly full executive, legislative and judicial powers practically unlimited by constitutional or legal restrictions, the system is often referred to as an "absolute monarchy." When the powers of the monarch are effectively limited and restricted by law (at least to insure respect for the subjects' recognized rights to personal freedom and property and often also to limit the monarch's powers of legislation and taxation), the system is normally referred to as "constitutional monarchy." [See also: republic, autocracy, oligarchy, aristocracy, monarchy, state, dictatorship, theocracy]