half-price (n.)

Old English half, halb (Mercian), healf (W. Saxon) "side, part," not necessarily of equal division (original sense preserved in behalf), from Proto-Germanic *halba- "something divided" (source also of Old Saxon halba, Old Norse halfr, Old Frisian, Middle Dutch half, German halb, Gothic halbs "half"), a word of no certain etymology. Perhaps from PIE root *skel- (1) "to cut," or perhaps a substratum word. Noun, adjective, and adverb all were in Old English.

Used also in Old English phrases, as in modern German, to mean "one half unit less than," for example þridda healf "two and a half," literally "half third." The construction in two and a half, etc., is first recorded c. 1200. Of time, in half past ten, etc., first attested 1750; in Scottish, the half often is prefixed to the following hour (as in German, halb elf = "ten thirty").

To go off half-cocked in the figurative sense "speak or act too hastily" (1833) is in allusion to firearms going off prematurely; half-cocked in a literal sense "with the cock lifted to the first catch, at which position the trigger does not act" is recorded by 1750. In 1770 it was noted as a synonym for "drunk." Bartlett ("Dictionary of Americanisms," 1848) writes that it was "a metaphorical expression borrowed from the language of sportsmen, and is applied to a person who attempts a thing in a hurry without due preparation, and consequently fails."

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.