Middle English sale, from late Old English sala "a sale, act of selling," which according to OED probably is from a Scandinavian source such as Old Norse sala "sale," but in either case from Proto-Germanic *salo (source also of Old High German sala, Swedish salu, Danish salg), from PIE root *sal- (3) "to grasp, take."

The specific application to a public auction is by 1670s. The sense of "a selling of shop goods at lower prices than usual" is attested by 1866. To be for sale "available for purchase, intended to be sold" is by 1610s; on sale in the same sense is by 1540s; the earlier form was to sale (late 14c.). Salariat "the salaried class" is by 1918, from French. Also see sales.

"not spontaneous or voluntary, strained, unnatural," 1570s, past-participle adjective from force (v.). Meaning "effected by an unusual application of force" is from 1590s. Related: Forcedly. The flier's forced landing attested by 1917.

also re-sale, "act of selling again; a second sale, a sale of what was sold before to the possessor," 1620s, from re- "back, again" + sale (n.).

"public sale, auction," 1680s, from Dutch vendu, from obsolete French vendue "sale, selling price," from vendre "to sell," from Latin vendere (see vend).

1938, the word, like the thing, a forced mating of lion and tiger.

1911, from Sanskrit hatha "force, violence, forced meditation" + yoga (see yoga).

early 15c., "pressed or forced upon" (the mind), past-participle adjective from impress (v.).

"of or pertaining to sale, sales, or the business of selling," word-forming element from genitive of sale (n.), by 1520s, in salesman. Cf. saleswork "work done for sale" (1775). For earlier use of similar formations, compare craftsman, oarsman, both Middle English. Sales tax is attested by 1886; sales clerk by 1863; sales associate by 1946. Sales representative is from 1910.

title of the ruler of Abyssinia, 1590s, from Amharic (Semitic) negush "king," from stem of nagasha "he forced, ruled."

1650s, "capable of being obtained for a price; that can be corrupted;" 1660s, "offered for sale," from French vénal, Old French venel "for sale" (of prostitutes, etc.; 12c.), from Latin venalis "for sale, to be sold; capable of being bribed," from venum (nominative *venus) "for sale," from PIE root *wes- (1) "to buy, sell" (source also of Sanskrit vasnah "purchase money," vasnam "reward," vasnayati "he bargains, haggles;" Greek onos "price paid, purchase," oneisthai "to buy"). Typically with a bad sense of "ready to sell one's services or influence for money and from sordid motives; to be bought basely or meanly."