Prose, n.
Etymology: [F. prose, L. prosa, fr. prorsus, prosus, straight forward, straight on, for proversus; pro forward + versus, p. p. of vertere to turn. See Verse.]
1. The ordinary language of men in speaking or writing; language not cast in poetical measure or rhythm; -- contradistinguished from verse, or metrical composition. I speak in prose, and let him rymes make. Chaucer. Things unattempted yet in prose or rhyme. Milton. 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 order. Coleridge.
2. Hence, language which evinces little imagination or animation; dull and commonplace discourse.
3. (R. C. Ch.)
A hymn with no regular meter, sometimes introduced into the Mass. See Sequence.
3 other Webster entries under this spelling
Prose, a.
1. Pertaining to, or composed of, prose; not in verse; as, prose composition.
2. Possessing or exhibiting unpoetical characteristics; plain; dull; prosaic; as, the prose duties of life.
Prose, v. t. [imp. & p. p. Prosed; p. pr. & vb. n. Prosing.]
1. To write in prose.
2. To write or repeat in a dull, tedious, or prosy way.
Prose, v. i.
1. To write prose. Prosing or versing, but chiefly this latter. Milton.
Shades of meaning
Fernald lists prose only as an antonym, under poetry.
He lists it without comment; the entries above explain its neighbors.