Lewis & Short

Heptăpylos, on (-os, c., -on, n.), adj., = ἑπτάπυλος, seven-gated, an epithet of the city of Thebes: Thebas Heptapylos accessimus, App. M. 4, p. 146.
Also in Latinized form: Cadmus Thebas Heptapylas condidit, Hyg. F. 275.