late 14c., reducen, "bring back" (to a place or state, a sense now obsolete), also "to diminish" (something), from Old French reducer (14c.), from Latin reducere "lead back, bring back," figuratively "restore, replace," from re- "back" (see re-) + ducere "bring, lead" (from PIE root *deuk- "to lead").
In Middle English largely with positive senses, including "bring back to virtue, restore to God; bring back to health." The specific meaning "bring to an inferior condition" is by 1570s; that of "bring to a lower rank" is by 1640s (military reduce to ranks is from 1802); that of "subdue by force of arms" is from 1610s. The sense of "to lower, diminish, lessen" is from 1787. Related: Reduced; reducing.
late 15c., "with subtraction of," from Latin minus "less," neuter of minor "smaller" (from PIE *mi-nu-, suffixed form of root *mei- (2) "small").
According to OED, this mathematical prepositional use in expressions of calculation was not in the classical Latin word and probably is from North Sea medieval commercial usage of Latin plus and minus to indicate surplus or deficiency of weight or measure.
The origin and original signification of the "minus sign" is disputed. As "deprived of, not having," by 1813. Of temperature, etc., "below 0 or the lowest point of positive reckoning, belonging to the inverse or negative side," by 1811.
In 17c. it began to replace be, ben as first person plural present indicative in standard English. The only non-dialectal survival of be in this sense is the powers that be. But in southwest England, we be (in Devonshire us be) remains non-standard idiom as a contradictory positive ("You people aren't speaking correct English." "Oh, yes we be!"), and we be has reappeared in African-American vernacular.
As a noun from early 15c., "that which affirms or asserts." American English affirmative action "positive or corrective effort by employers to prevent discrimination in hiring or promotion" is attested from 1935 with regard to labor unions (reinstatement of fired members, etc.). The specific racial sense is attested from 1961; by late 1970s the sense had shifted toward pro-active methods such as hiring quotas. Related: Affirmatively.
Until 1500s, pronounced to rhyme with kiss. Dialectal use for all persons (I is) is in Chaucer. Phrase it is what it is, indicating resigned acceptance of an unpleasant but inevitable situation or circumstance about which nothing truly positive can be said, is attested by 2001.
mid-14c., "eager or inordinate desire for honor or preferment," from Old French ambicion (13c.), or directly from Latin ambitionem (nominative ambitio) "a going around," especially to solicit votes, hence "a striving for favor, courting, flattery; a desire for honor, thirst for popularity," noun of action from past-participle stem of ambire "to go around, go about," from amb- "around" (from PIE root *ambhi- "around") + ire "go" (from PIE root *ei- "to go").
Rarely used in English or Latin the literal sense. In early use in English always pejorative, of inordinate or overreaching desire; ambition was grouped with pride and vainglory, and sometimes meant little more than "arrogance." Neutral or positive senses are modern. Meaning "object of strong desire" is from c. 1600.
late 14c., "inordinate self-esteem, arrogance," especially "self-satisfaction over one's accomplishments or qualities, vainglory" (early 15c.), from Old French elacion "elation, conceit, arrogance, vanity," from Latin elationem (nominative elatio) "a carrying out, a lifting up," noun of action from elatus "elevated," form used as past participle of efferre "carry out, bring out, bring forth, take away," from assimilated form of ex "out" (see ex-) + lātus "carried, borne" (see oblate (n.)), past participle of the irregular verb ferre "carry" (from PIE root *bher- (1) "to carry," also "to bear children"). Metaphoric sense of "a lifting of spirits" was in Latin and has always been the principal meaning in English. More positive sense of "buoyancy, joyfulness" is from 1750 in English.
late 14c., "grasp with the senses or mind;" early 15c. as "grasp, take hold of" physically, from Latin apprehendere "to take hold of, grasp," from ad "to" (see ad-) + prehendere "to seize" (from prae- "before;" see pre- + -hendere, from PIE root *ghend- "to seize, take"). Often "to hold in opinion but without positive certainty."
We "apprehend" many truths which we do not "comprehend" [Richard Trench, "On the Study of Words," 1856]
The metaphoric extension to "seize with the mind" took place in Latin and was the sole sense of cognate Old French aprendre (12c., Modern French appréhender); also compare apprentice). Specific meaning "seize in the name of the law, arrest," is from 1540s. Meaning "be in fear of the future, anticipate with dread" is from c. 1600. Related: Apprehended; apprehending.
And to show how entire the neglect and confusion have been, they speak in the same breath of all these explosions, and of the explosion of a mixture of hydrogen and oxygen, the result of which, instead of being a gas or an enlargement of bulk, a positive quantity, is a negative one. It is a vacuum, in a popular sense, because the produce is water. The result is an implosion (to coin a word), not an explosion .... ["Gas-light," Westminster Review, October 1829]
In early use often in reference to effect of deep sea pressures, or in phonetics. Figurative sense is by 1960.
c. 1400, negatif, "expressing denial" (a sense now rare or obsolete), from Anglo-French negatif (early 14c.), Old French negatif (13c.) and directly from Latin negativus "that which denies," from negat-, past-participle stem of negare "deny, say no" (see deny).
The meaning "expressing negation" is from c. 1500; that of "characterized by absence of that which is affirmative or positive" is from 1560s. Algebraic sense, denoting quantities which are a subtraction from zero, is from 1670s. The electricity sense is from 1755.
Negative Capability, that is when a man is capable of being in uncertainties, Mysteries, doubts without any irritable reaching after fact and reason. [John Keats, letter, Dec. 21, 1817]