Lewis & Short

Simbrŭvĭum, ii, n., a district in Latium, abounding in hills and springs of water, Sil. 8, 371.
Hence, Simbrŭīnus, a, um, adj., of or belonging to Simbruvium: colles, Tac. A. 11, 13: stagna, id. ib. 14, 22.