Principal
Part of speech: adjective
Definition: Primary; most important in a group.
Part of speech: noun
Definition: The money originally invested or loaned, on which basis interest and returns are calculated The principal administrator of a school One who directs another (the agent) to act on one's behalf A company represented by a sales person
Director
Part of speech: noun
Definition: One who directs; the person in charge of managing a department or directorate (e.g., director of engineering), project, or production (as in a show or film, e.g., film director).A device that displays graphical information concerning the targets of a weapons system in real time.The common axis of symmetry of the molecules of a liquid crystal.