A 'Monarchy' is a form of government in which supreme power is absolutely or nominally lodged with an individual, who is the head of state, often for life or until abdication, and "is wholly set apart from all other members of the state." The person who heads a monarchy is called a monarch. It was a common form of government in the world during the ancient and medieval times.
There is no clear definition of monarchy. Holding unlimited political power in the state is not the defining characteristic, as many constitutional monarchies such as the United Kingdom and Thailand are considered monarchies.
Hereditary rule is often a common characteristic, but elective monarchies are also considered monarchies