“Exposition: Exposition, or expository writing, is traditionally understood as writing that aims to transmit information to presumably interested parties as distinguished from writing that aims to persuade the reader. As there will be elements of persuasive writing in expository, so also will there be elements of the expository in persuasive.
In the following discussion, however, the perspective is that of rhetorical analysis, which regards all written communication (including the note on the refrigerator door) as guided by a communicative/persuasive purpose. Exposition is, then, that type of prose writing that attempts to create, in its target audience, the attitude that the writer is objectively presenting the facts relative to a given subject. Exposition thus is not a division of prose discourse according to intent, but rather represents a tone that the writer wishes the reader to accept as ‘factual.’ The writer of exposition cultivates a tone designed to allow (encourage) the reader to think that the writer has no specific interest in, or position in regard to, the subject matter presented.
Excerpted from: Trail, George Y. Rhetorical Terms and Concepts: A Contemporary Glossary. New York: Harcourt Brace, 2000.