Handsale

Anciently, among all the northern nations, shaking of hands was held necessary to bind a bargain,—a custom still retained in verbal contracts. A sale thus made was called "handsale," (venditio per mutuam manum complexionem.) In process of time the same word was used to signify the price or earnest which was given immediately after the shaking of hands or instead thereof.

2 Bl. Comm. 448.