v. 1. to set forth reasons; to explain or expound. [ WordNet 1.5 ]

2. to make external.
Syn. -- externalize, externalise. [ WordNet 1.5 ]

n. [ L. expositio, fr. exponere, expositum: cf. F. exposition. See Expound. ] 1. The act of exposing or laying open; a setting out or displaying to public view. [ 1913 Webster ]

2. The act of expounding or of laying open the sense or meaning of an author, or a passage; explanation; interpretation; the sense put upon a passage; a law, or the like, by an interpreter; hence, a work containing explanations or interpretations; a commentary. [ 1913 Webster ]

You know the law; your exposition
Hath been most sound. Shak. [ 1913 Webster ]

3. Situation or position with reference to direction of view or accessibility to influence of sun, wind, etc.; exposure; as, an easterly exposition; an exposition to the sun. [ Obs. ] Arbuthnot. [ 1913 Webster ]

4. A public exhibition or show, as of industrial and artistic productions; as, the Paris Exposition of 1878. [ A Gallicism ] [ 1913 Webster ]

a. Serving to explain; expository. Bp. Pearson. [ 1913 Webster ]

n. [ L. See Expound. ] One who, or that which, expounds or explains; an expounder; a commentator. Bp. Horsley. [ 1913 Webster ]

a. Pertaining to, or containing, exposition; serving to explain; explanatory; illustrative; exegetical. [ 1913 Webster ]

A glossary or expository index to the poetical writers. Johnson.