Essay
An essay (, ESS-ay) is, generally, a piece of writing that gives the author's own argument, but the definition is vague, overlapping with those of a letter, a paper, an article, a pamphlet, and a short story. Essays have been sub-classified as formal and informal: formal essays are characterized by "serious purpose, dignity, logical organization, length," whereas the informal essay is characterized by "the personal element (self-revelation, individual tastes and experiences, confidential manner), humor, graceful style, rambling structure, unconventionality or novelty of theme," etc.