Lewis & Short

Arpi, ōrum, m.,

  1. I. a city in Apulia, earlier called Argyripa (q. v.), now Arpa, Plin. 3, 11, 16, § 104; cf. Mann. Ital. II. 82 sq.
    Hence,
  2. II. Derivv.:
    1. A. Arpīnus, a, um, adj., of or from Arpi: Dasius Altinius Arpinus, Liv. 24, 45; Arpīni, ōrum, m., the inhabitants of Arpi, id. 24, 47.
    2. B. Ar-pānus, a, um, adj., pertaining to Arpi, Front. Col.; Arpāni, ōrum, m., the inhabitants of Arpi, Plin. 3, 11, 16, § 103.