prix fixe

late 14c., "set (one's eyes or mind) on something" (a figurative use), probably from Old French verb *fixer, from fixe "fixed," from Latin fixus "fixed, fast, immovable; established, settled," past-participle adjective from figere "to fix, fasten, drive, thrust in; pierce through, transfix," also figurative, from PIE root *dheigw- "to pierce, stick in;" hence "to fix, fasten."

Sense of "fasten, attach" is c. 1400; that of "to make (colors, etc.) fast or permanent" is from 1660s. The meaning "settle, assign" evolved into "adjust, arrange" (1660s), then "to repair" (1737), but this sometimes was objected to (see below). Sense of "tamper with" (a fight, a jury, etc.) is from 1790. As euphemism for "castrate a pet" it dates from 1930. Related: Fixed; fixing.

To fix is to make fast, or permanent; to set immoveably, &c.: hence, to fix a watch, is to stop it, or prevent it from 'going;' which, it must be admitted, is a very unsatisfactory mode of repairing that article. [Seth T. Hurd, "A Grammatical Corrector; or, Vocabulary of the Common Errors of Speech," 1847]

c. 1200, pris, "non-monetary value, worth; praise," later "recompense, prize, reward," also "sum or amount of money which a seller asks or obtains for goods in market" (mid-13c.), from Old French pris "price, value, wages, reward," also "honor, fame, praise, prize" (Modern French prix), from Late Latin precium, from Latin pretium "reward, prize, value, worth" (from PIE *pret-yo-, suffixed form of *pret-, extended form of root *per- (5) "to traffic in, to sell").

Praise, price, and prize began to diverge in Old French, with praise emerging in Middle English by early 14c. and prize, with the -z- spelling, evident by late 1500s. Having shed the extra Old French and Middle English senses, price again has the ancient sense of the Latin original. To set (or put) a price on someone, "offer a reward for capture" is from 1766.