Lewis & Short

Arsăces, is m., = Ἀρσάκης,

  1. I. the first king of the Parthians, Just. 41, 5.
  2. II. Derivv.
    1. A. Arsăcĭdae, ārum, m. (gen. plur. Arsacidūm, Luc. 10, 51), successors of Arsaces, Tac. H. 1, 40; Luc. 1, 108; 8, 217; 8, 306 al.
    2. B. Arsăcĭus, a, um, adj., Arsacian, poet. for Parthian, Mart. 9, 36.