Lewis & Short

Augustēus, a, um, adj. [Augustus], of or belonging to Augustus, Augustan: lex, Front. Col. p. 121 Goes: termini, id. ib. pp. 119, 121, 122: charta, also called regia, Isid. Orig. 6, 10, 2 (cf. Plin. 13, 12, 23, § 74): marmor, v. 2. Augustus, II.
Hence, Augustēum, i, n., a temple built in honor of Augustus, Inscr. Orell. 642.