Prose is ordinary writing (both fiction and nonfiction) as distinguished from verse. Most essays, compositions, reports, articles, research papers, short stories, and journal entries are types of prose writings.
In his book The Establishment of Modern English Prose (1998), Ian Robinson observed that the term prose is "surprisingly hard to define… We shall return to the sense there may be in the old joke that prose is not verse."
In 1906, English philologist Henry Cecil Wyld suggested that the "best prose is never entirely remote in form from the best corresponding conversational style of the period" (The Historical Study of the Mother Tongue).
From the Latin, "forward" + "turn"
"I wish our clever young poets would remember my homely definitions of prose and poetry: that is, prose = words in their best order; poetry = the best words in the best order."
(Samuel Taylor Coleridge, Table Talk, July 12, 1827)
Philosophy Teacher: All that is not prose is verse; and all that is not verse is prose.
M. Jourdain: What? When I say: "Nicole, bring me my slippers, and give me my night-cap," is that prose?
Philosophy Teacher: Yes, sir.
M. Jourdain: Good heavens! For more than 40 years I have been speaking prose without knowing it.
(Molière, Le Bourgeois Gentilhomme, 1671)
"For me, a page of good prose is where one hears the rain and the noise of battle. It has the power to give grief or universality that lends it a youthful beauty."
(John Cheever, on accepting the National Medal for Literature, 1982)
"Prose is when all the lines except the last go on to the end. Poetry is when some of them fall short of it."
(Jeremy Bentham, quoted by M. St. J. Packe in The Life of John Stuart Mill, 1954)
"You campaign in poetry. You govern in prose."
(Governor Mario Cuomo, New Republic, April 8, 1985)
Transparency in Prose
"One can write nothing readable unless one constantly struggles to efface one's own personality. Good prose is like a window pane."
(George Orwell, "Why I Write," 1946)
"Our ideal prose, like our ideal typography, is transparent: if a reader doesn't notice it, if it provides a transparent window to the meaning, then the prose stylist has succeeded. But if your ideal prose is purely transparent, such transparency will be, by definition, hard to describe. You can't hit what you can't see. And what is transparent to you is often opaque to someone else. Such an ideal makes for a difficult pedagogy."
(Richard Lanham, Analyzing Prose, 2nd ed. Continuum, 2003)
"Prose is the ordinary form of spoken or written language: it fulfills innumerable functions, and it can attain many different kinds of excellence. A well-argued legal judgment, a lucid scientific paper, a readily grasped set of technical instructions all represent triumphs of prose after their fashion. And quantity tells. Inspired prose may be as rare as great poetry--though I am inclined to doubt even that; but good prose is unquestionably far more common than good poetry. It is something you can come across every day: in a letter, in a newspaper, almost anywhere."
(John Gross, Introduction to The New Oxford Book of English Prose. Oxford Univ. Press, 1998)
A Method of Prose Study
"Here is a method of prose study which I myself found the best critical practice I have ever had. A brilliant and courageous teacher whose lessons I enjoyed when I was a sixth-former trained me to study prose and verse critically not by setting down my comments but almost entirely by writing imitations of the style. Mere feeble imitation of the exact arrangement of words was not accepted; I had to produce passages that could be mistaken for the work of the author, that copied all the characteristics of the style but treated of some different subject. In order to do this at all it is necessary to make a very minute study of the style; I still think it was the best teaching I ever had. It has the added merit of giving an improved command of the English language and a greater variation in our own style."
(Marjorie Boulton, The Anatomy of Prose. Routledge & Kegan Paul, 1954)