what is an exposition?

Exposition n
1 a clear explanation
2 a show in which works of art etc are shown to the public

That is what an expository essay is. It comprehensively proves a point to its readers, just as an expo presents its works to the public.

But an expository essay is no casual show. The author carefully picks his words and chooses his sentences, methodically piecing together his paragraphs to ultimately create a piece of work which harnesses the power to convince.

There exists exposition everywhere around us, only taking different forms. Advertisements, forums and commentaries. These are all attempts to convince, whether effective or not. This is exposition in action.