Lewis & Short

aspis, ĭdis, f. (acc. Gr. aspida, Luc. 9, 701; plur. aspidas, Cic. N. D. 3, 19, 47) [ἀσπίς, com. shield, rarely an asp; this order of frequency is reversed in Lat.].

  1. I. The asp, viper: Coluber, Linn.; Plin. 29, 4, 18, § 65: aspide ad corpus admoto, Cic. Rab. Post. 9: si scieris aspidem occulte latere uspiam, id. Fin. 2, 18, 59; Isid. Orig. 12, 4, 12.
  2. II. A shield, = ἀσπίς, Just. Nov. 85 fin.