Emily Dickinson Lexicon

SOAP, n. [Sax. sape; D. zeep; G. seife; Sw. såpa; Dan. sæbe; Fr. savon; It. sapone; Sp. xabon; L. sapo; Gr. σαπων; Arm. savann; W. sebon; Hindoo, saboon, savin; Gipsy, sapuna; Pers. سَابُونْ sabun; Ar. سَابُونٌ sabunon. Class Sb, No. 29.]

A compound of one or more of the oil-acids, more especially with the metallic alkalies potassa or soda, but also with some other salifiable bases. The most common soaps are either margarates or oleates of potassa or soda, made by boiling some common oil with the ley of wood-ashes; used in washing and cleansing, in medicine, &c. Common soap is an unctuous substance.