Lewis & Short

altrinsĕcus, adv. [for alterim-secus from alter-secus] (ante- and post-class.; ante-class. only in Plaut. in the foll. exs.).

  1. I. At or on the other side: quid, malum, adstas? quin retines altrinsecus? Plaut. Mil. 2, 5, 36; so id. Ps. 3, 2, 73; 1, 3, 123; id. Rud. 4, 4, 114; id. Merc. 5, 4, 16: fenestrae, quae foris (outwardly) urbem prospiciunt, et altrinsecus (within) fores, etc., App. M. 1, p. 111, 41; so id. ib. 2, p. 122, 39.
    With gen.: aedium, App. M. 3, p. 137, 2.
  2. II. (Postclass.) From or on both sides, = ab utrāque parte: venientes altrinsecus, Lact. 8, 6; so Amm. 25, 7; Treb. Poll. Gall. p. 309; Fulg. Prisc. Serm. p. 560, 9: utrasque partes contra se altrinsecus posuit, over against each other on each side, Vulg. Gen. 15, 10: bracchiola duo altrinsecus (fecit), stays on each side, ib. 2 Par. 9, 18.
    Cf. Hand, Turs. I. pp. 282-284.