The Collaborative International Dictionary of English v.0.48:
Instructor \In*struct"or\, n. [L., a preparer: cf. F. instructeur.] [Written also instructer.] One who instructs; one who imparts knowledge to another; a teacher. [1913 Webster]The Collaborative International Dictionary of English v.0.48:
Instructer \In*struct"er\, n. See Instructor. [1913 Webster]