πύλη
Alt. πψ́λη, ἡ,
I. "one wing of a pair of double gates", Hdt.: mostly in pl. "the gates of a town", opp. to θύρα "(a house-door)", Il., attic
2. in Trag., sometimes, of the "house-door."
3. Ἀΐδαο πύλαι, periphr. for "the nether world, hell", Hom., Aesch., etc.
II. generally, "an entrance", of the liver, π. καὶ δοχαὶ χολῆς "the orifice" and receptacle of gall, Eur.
2. "an entrance into a country through mountains, a mountain-pass", Hdt.: esp. Πύλαι, ῶν, αἱ, the common name for Θερμοπύλαι, "the pass round the mountains" from Thessaly to Locris, considered "the gates" of Greece, id=Hdt.; so, of "the pass" from Syria into Cilicia, Xen., etc.
3. also of "narrow straits", by which one enters a broad sea, ἐπ᾽ αὐταῖς λίμνης π., of the Thracian Bosporus, Aesch.; ἐν πύλαις, of the Euripus, Eur.