1911 Encyclopædia Britannica/Lye

LYE (O. Eng. léag, cf. Dutch loog, Ger. Lauge, from the root meaning to wash, see in Lat. lavare, and Eng. “lather,” froth of soap and water, and “laundry”), the name given to the solution of alkaline salts obtained by leaching or lixiviating wood ashes with water, and sometimes to a solution of a caustic alkali. Lixiviation (Lat. lixivium, lye, lix, ashes) is the action of separating, by the percolation of water, a soluble from an insoluble substance. “Leaching,” the native English term for this process, is from “leach,” to water, the root probably being the same as in “lake.”