Lewis & Short

Dĭŏvis or Dĭjŏvis, is, m. [collat. form of Jovis, old nom. for later Juppiter, q. v.; cf. Diespiter], the old Italian name for Juppiter, acc. to Varr. L. L. 5, § 66 Müll.; Gell. 5, 12, 1 and 6; Inscr. in Bullet. del Inst. 1846.