A person responsible for governing a society, institution, etc.: a director, a manager.

A chief actor or doer; a principal agent. The person chiefly responsible for some action, an initiator or leader; spec. (Law) a person directly…

The head or presiding officer of a society, institution, etc., e.g. of certain colleges (in Oxford, Cambridge, Yale, and elsewhere), guilds…

The title given to the head or presiding officer of certain colleges and schools, hospitals, etc.

An appointed or elected head of any gathering, who presides over meetings and proceedings. The person elected to preside over the meetings and…

gen. Any principal, chief, or leading minister, servant, or agent. Obsolete.

The first or chief minister of any ruler; the chief officer of an institution. Now rare.