Lewis & Short

vēnum, i, v. 2. venus.

vēnum-do or vēnun-do (vaen-; also separately, vēnum do, v. infra), dĕdi, dătum, 1, v. a. [2. venus-do, whence also vendo, by contraction], to sell, used chiefly of the sale of captured slaves (not in Cic.) hostes praeter senatores omnes venumdati sunt, Liv. 4, 29, 4: multitudo alia civium Campanorum venum data, id. 26, 16, 6: Numidae puberes interfecti, alii omnes venundati, Sall. J. 91, 6: captivos, Suet. Aug. 21; Tac. A. 14, 33; 13, 39; id. H. 1, 68; id. Agr. 28; Flor. 4, 12, 52: tuque, o Minoa venundata Scylla figura, tondes, etc., sold for, i. e. bribed by, Prop. 3, 19 (4, 18), 21: sententiam, to put up for sale, Tac. A. 11, 22 fin.
In tmesi: se venum a principibus datos Poeno, Liv. 24, 47, 6: praedam venum aut dono datum, Sall. H. 1, 41, 17 Dietsch.

2. vēnus, ūs, m., or vēnum (vaen-), i, n. (occurring only in the forms venui, veno, and venum) [Gr. ὦνος, price; ὠνή, purchase; cf. Sanscr. vasuas, price; vasuam, wages; and perh. Germ. Gewinn], sale.

      1. a. Dat.
        1. (α) Form venui (late Lat.): rogavit haberetne venui lacte? App. M. 8, p. 210, 12: cantherium venui subicere, id. ib. 8, p. 221, 29.
        2. (β) Form veno (post-Aug.): posita veno irritamenta luxus, Tac. A. 14, 15: quae veno exercerent, id. ib. 13, 51.
      2. b. Acc. venum (class.): dare aliquem venum, to sell, Liv. 24, 47, 6: venum cuncta dari, Claud. in Rufin. 1, 179; hence the compound venumdo, q. v.: ut ejus familia ad aedem Cereris venum iret, Liv. 3, 55, 7: pileatos servos venum solitos ire, Gell. 7, 4, 1: venum iturum, Sen. Const. 3, 2: seque et sua tradita venum Castra videt, Luc. 4, 206: venum redibat, Claud. in Eutr. 1, 37.