Lewis & Short

Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.

Firmĭus, ii, m., a Roman proper name, e. g. Firmius Catus, Tac. A. 2, 27; 4, 31.
Hence, Firmĭānus, a, um, adj., of Firmius, an unknown silver-worker of that name: Firmiana vasa, Plin. 33, 11, 49, § 139 (Jan. Furniana).