Lewis & Short

Tergeste, is, n., the northernmost town on the coast of Istria, the mod. Trieste, Mel. 2, 4, 3; Plin. 3, 18, 22, § 127; Vell. 2, 110, 4.
Called also Tergestum, Mel. 2, 3, 13.
Hence, Tergestīnus, a, um, adj., of or belonging to Tergeste, Tergestine. sinus, the mod. Golfo di Trieste, Plin. 3, 18, 22, § 127.
Plur subst. Tergestīni, ōrum, m., the inhabitants of Tergeste, the Terges tines, Hirt B G 8, 24.