A monarchy, from the Greek μονος, "one," and αρχειν, "to rule," is a form of government in which a single person, or monarch, is the Head of State.
A monarch typically acquires the position through birth or conquest. Most monarchs occupy the position for life, although some choose to retire and pass it on to their heir. Most monarchs choose their kin as heirs, while others may choose someone they consider suitable.
There are chiefly the following types of monarchies present in modern times: Absolute monarchy, Constitutional monarchy, Semi-constitutional monarchy, and Commonwealth realm. There are different types of monarchies also present, for example, the United Arab Emirates and Malaysia have a Federal constitutional monarchy. While the Head of State of Malaysia is a monarch of one of the states, a few of the states do not have a monarch.