Lewis & Short

Coelē Syrĭa, or in one word Coe-lēsyrĭa, ae, f., = Κοίλη Συρἰα (lit. Hollow Syria), Cœlesyria, between Libanus and Antilibanus, Plin. 5, 20, 17, § 77; Liv. 33, 19, 8; 42, 29, 9; Curt. 4, 1, 4; cf. id. 4, 5, 9.
Called simply Coele, Mel. 1, 11, 1; Plin. 5, 12, 13, § 66; 5, 23, 19, § 81 al.; gen. COELES SYRIAE, Inscr. Fabr. 10, n. 215; acc. Coelen Syriam, Liv. 45, 11, 6.
Syria Coele, Plin. 21, 18, 72, § 120.