late O.E. sala "a sale," from O.N. sala "sale," from P.Gmc. *salo (cf. O.H.G. sala, Swed. salu, Dan. salg), from root *sal-, source of *saljan (cf. O.E. sellan; see sell). Sense of "a selling of shop goods at lower prices than usual" first appeared 1866. Salesman is from 1523; salesmanship first attested 1880.