Expositor

·noun One who, or that which, expounds or explains; an expounder; a commentator.

expositor
expŏsĭtor, ōris, m. [expono], an expounder , interpreter : somniorum, Firm. Math. 13, 5: juris, Ca...

A New Latin Dictionary by Charlton T. Lewis Ph.D. and Charles Short, LL. D.