What is a making clear; the act of elucidating or that which elucidates, as an explanation, an exposition, an illustration; as, one example may serve for further elucidation of the subject called?

elucidation — A making clear; the act of elucidating or that which elucidates, as an explanation, an exposition, an illustration; as, one example may serve for further elucidation of the subject. (Webster's 1913.)