What is Chief Magistrate?

Legal Definition
Chief magistrate is a public official, executive or judicial, whose office is the highest in its class. Historically, the two different meanings of magistrate have often overlapped and refer to, as the case may be, to a major political and administrative officer (usually at a subnational or colonial level) or a judge and barrister.
-- Wikipedia
Legal Definition
The head of the executive department of government of a nation, state, or municipal corporation. Mclntire v. Ward, 3 Yeates (Pat) 424.
-- Black's Law Dictionary
Legal Definition
The highest or principal executive officer of a state (the governor) or of the United States (the president)
-- Black's Law Dictionary