Pharaoh is the vernacular term often used for the monarchs of ancient Egypt, who ruled from the First Dynasty until the annexation of Egypt by the Roman Republic in 30 BCE. However, regardless of gender, "king" was the term used most frequently by the ancient Egyptians for their monarchs through the middle of the Eighteenth Dynasty during the New Kingdom. The earliest confirmed instances of "pharaoh" used contemporaneously for a ruler were a letter to Akhenaten or an inscription possibly referring to Thutmose III.

A monarch is a head of state for life or until abdication, and therefore the head of state of a monarchy. A monarch may exercise the highest authority and power in the state, or others may wield that power on behalf of the monarch. Usually a monarch either personally inherits the lawful right to exercise the state's sovereign rights or is selected by an established process from a family or cohort eligible to provide the nation's monarch. Alternatively, an individual may proclaim oneself monarch, which may be backed and legitimated through acclamation, right of conquest or a combination of means.