Lewis & Short

Signĭa, ae, f., an ancient town in Latium which produced an astringent wine, now Segni, Liv. 1, 56; 2, 21 fin.; 8, 3; 32, 2; Plin. 14, 6. 8, § 65; Sil. 8, 380.
Hence, Signīnus, a, um, adj., of or belonging to Signia, Signian: vinum, Cels. 4, 5; 4, 19 fin.; Mart. 13, 116: pira, Col. 5, 10, 18; Plin. 15, 15, 16, § 55; Juv. 11, 73 al.: opus, a kind of plaster for walls and pavements, made of potsherds and lime, Vitr. 2, 4; 7, 11; 8, 7; Col. 1, 6, 12; 8, 15, 3; 8, 17, 1.
As subst.

    1. 1. Signīnum, i, n., = Signinum opus, Col. 9, 1, 2; Plin. 35, 12, 46, § 165.
    2. 2. Signīni, ōrum, m., the inhabitants of Signia, Signians, Liv. 27, 10; Plin. 3, 5, 9, § 64.