Origin and history of wash

"apply water or liquid to for purposes of cleansing," Middle English washen, from Old English wascan "cleanse, bathe," also "cleanse spiritually" (of sin, guilt); transitive sense in late Old English; from Proto-Germanic *watskan "to wash" (source also of Old Norse vaska, Middle Dutch wasscen, Dutch wassen, German waschen), from PIE root *wed- (1) "water; wet." Related: Washed; washing.

In the literal sense used mainly of clothes in Old English (the principal verb for washing the body, dishes, etc. being þwean). Old French gaschier "to stain, soil; soak, wash" (Modern French gâcher) is from Frankish *waskan, from the same Germanic source. Italian guazzare also is a Germanic loan-word. See gu-.

By 1530s as "rinse the mouth." To wash up "clean table utensils after a meal" is from 1751 (compare washed-up). To wash down (solid food, with a liquid) is by c. 1600. To wash (one's) hands of "forsake involvement in" (an iniquity, etc.) is attested by 1550s (Lady Jane Grey), an image from Pilate in Matthew xxvii.24.

late Old English wæsc "act of washing" (clothes or other articles), from wash (v.). The meaning "clothes set aside to be washed" is attested from 1789; the general sense of "an act of washing" is by 1825.

The meaning "thin coat of paint" is recorded from 1690s; the sense of "land alternately covered and exposed by the sea" is by mid-15c. In reference to a thin medicinal lotion by 1620s; of a liquid cosmetic from 1630s. By mid-15c. as "waste-water after a washing," extended to kitchen swill generally, hence "food for swine" (1580s). Also in reference to the rough or broken water left behind by a vessel as it moves.

By 1891 in Stock Exchange vernacular in reference to a fictitious sale amounting to a transfer from a seller to a buyer, perhaps from the notion of one hand washing the other.

Figurative come out in the wash "come clear eventually" is by 1903.