"confused conflict among many persons," 1640s, from French mêlée, from Old French meslee "brawl, confused fight; mixture, blend" (12c.), noun use of fem. past participle of mesler "to mix, mingle" (see meddle). See also medley. Borrowed in Middle English as melle but it was lost and then reborrowed 17c.
1620s, of persons, "to serve as a soldier" (now rare), from Latin militatum, past participle of militare "serve as a soldier," from miles "soldier" (see military (adj.)). The sense developed via "to be in conflict with, be at variance" to "be evidence" for or against, "have weight or force in determining anything" (1640s). Related: Militated; militating; militation.
1560s, of persons, "to transgress," from French contravenir "to transgress, decline, depart," from Late Latin contravenire "to come against, oppose," in Medieval Latin "to transgress, break (a law)," from Latin contra "against" (see contra (prep., adv.)) + venire "to come" (from PIE root *gwa- "to go, come"). Of actions or things, "come or be in conflict with," 1660s. Related: Contravened; contravening.
"unanswerable fact or argument," 1837, slang, something that "settles" a debate, discussion, conflict, etc.; hence "something astonishing" (1880s). Probably an agent noun from cork (v.) on the notion is of putting a cork in a bottle as an act of finality. Corker in the literal sense of "one who or that which corks" is from 1880.
c. 1300, "freedom from disturbance or conflict; calm, stillness," from Old French quiete "rest, repose, tranquility" and directly from Latin quies (genitive quietis) "a lying still, rest, repose, peace" (from PIE root *kweie- "to rest, be quiet").
From late 14c. as "inactivity, rest, repose;" from c. 1400 as "absence of noise."