discover v.

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).

mid-12c., "protect or defend from harm," from Old French covrir "to cover, protect, conceal, dissemble" (12c., Modern French couvrir), from Late Latin coperire, from Latin cooperire "to cover over, overwhelm, bury," from assimilated form of com-, here perhaps an intensive prefix (see com-), + operire "to close, cover," from PIE compound *op-wer-yo-, from *op- "over" (see epi-) + root *wer- (4) "to cover."

Sense of "to hide or screen" is from c. 1300, that of "to put something over (something else)" is from early 14c. Sense of "spread (something) over the entire extent of a surface" is from late 14c. Military sense of "aim at" is from 1680s; newspaper sense first recorded 1893; use in U.S. football dates from 1907. Betting sense "place a coin of equal value on another" is by 1857. Of a horse or other large male animal, as a euphemism for "copulate with" it dates from 1530s.

Meaning "to include, embrace, comprehend" is by 1868. Meaning "to pass or travel over, move through" is from 1818. Sense of "be equal to, be of the same extent or amount, compensate for" is by 1828. Sense of "take charge of in place of an absent colleague" is attested by 1970.