What is an exposition?

After cheating and using a dictionary: An exposition is a writing or speech primarily intended to convey information or to explain.

After thinking: To me, an exposition is an argument for or against a point, where a writer attempts to persuade the reader to believe his stand. Of course, there has to be evidences to support his points, and the writer also has the job of showing how those evidences support the points. Furthermore, the writer also has to provide a contrary viewpoint so that the exposition is balanced and unbiased.