Origin and history of discrepancy

Late Old English ræfen, refen, earlier hræfn (Mercian), hrefn, hræfn (Northumbrian, West Saxon), from Proto-Germanic *khrabanaz (source also of Old Norse hrafn, Danish ravn, Dutch raaf, Old High German hraban, German Rabe "raven," Old English hroc "rook"), from a PIE root imitative of harsh sounds (compare Latin crepare "to creak, clatter," cornix "crow," corvus "raven;" Greek korax "raven," korōnē "crow;" Old Church Slavonic kruku "raven;" Lithuanian krauklys "crow"). Old English, by a normal alteration of -fn, also used hræmn, hremm.

A larger species of crow common in Europe and Asia, noted for its lustrous black plumage and raucous voice; the raven is "popularly regarded as a bird of evil omen and mysterious character" [OED].

Raven mythology shows considerable homogeneity throughout the whole area [northern regions of the northern hemisphere] in spite of differences in detail. The Raven peeps forth from the mists of time and the thickets of mythology, as a bird of slaughter, a storm bird, a sun and fire bird, a messenger, an oracular figure and a craftsman or culture hero. [Edward A. Armstrong, "The Folklore of Birds," 1958]

The Quran connects the raven with Cain's murder of Abel, but in Christianity the bird plays a positive role in the stories of St. Benedict, St. Paul the Hermit, St. Vincent, etc. Poe's poem was published in 1845. It was anciently believed to live to a great age but also to be wanting in parental care. The raven standard was the flag of the Danish vikings. The vikings, like Noah, were said to have used the raven to find land when at sea. "When uncertain of their course they let one loose, and steered the vessel in his track, deeming that the land lay in the direction of his flight; if he returned to the ship, it was supposed to be at a distance" [Charles Swainson, "The Folk Lore and Provincial Names of British Birds," London, 1886]. As an English name for the constellation Corvus by late 14c.

word-forming element of Latin origin meaning 1. "lack of, not" (as in dishonest); 2. "opposite of, do the opposite of" (as in disallow); 3. "apart, away" (as in discard), from Old French des- or directly from Latin dis- "apart, asunder, in a different direction, between," figuratively "not, un-," also "exceedingly, utterly." Assimilated as dif- before -f- and to di- before most voiced consonants.

The Latin prefix is from PIE *dis- "apart, asunder" (source also of Old English te-, Old Saxon ti-, Old High German ze-, German zer-). The PIE root is a secondary form of *dwis- and thus is related to Latin bis "twice" (originally *dvis) and to duo, on notion of "two ways, in twain" (hence "apart, asunder").

In classical Latin, dis- paralleled de- and had much the same meaning, but in Late Latin dis- came to be the favored form and this passed into Old French as des-, the form used for compound words formed in Old French, where it increasingly had a privative sense ("not"). In English, many of these words eventually were altered back to dis-, while in French many have been altered back to de-. The usual confusion prevails.

As a living prefix in English, it reverses or negatives what it is affixed to. Sometimes, as in Italian, it is reduced to s- (as in spend, splay, sport, sdain for disdain, and the surnames Spencer and Spence).