A.neck, narrow passage, esp. of the body, neck, Emp.100.19; “ἰ. καὶ ὅρος τῆς τε κεφαλῆς καὶ τοῦ στήθεος” Pl.Ti.69e: metaph., “βίου βραχὺν ἰσθμόν” S.Fr.568 (lyr.).
2. pharynx, fauces, Gal.18(2).961, Aret.SA1.6.
II. neck of land between two seas, isthmus, “ὁ ἰ. τῆς Χερσονήσου” Hdt.6.36; of Athos, Id.7.22; “Κιμμερικός” A.Pr.729; “ὁ ἰ. τῆς Παλλήνης” Th.1.56; ὁ Λευκαδίων ἰ. Id.3.81.
2. Ἰσθμός (also Ἰθμός SIG507 (Delph., iii B.C.), cf. foreg.) ὁ (ἡ in Pi., as O.7.81, 8.48), the Isthmus of Corinth, Hdt.8.40, etc.; Ἰσθμοῦ δειράς, αὐχὴν Ἰσθμοῦ, Pi.I.1.9, B.2.7; dat. Ἰσθμῷ prob. f.l. for Ἰσθμοῖ (q.v.) in Th.5.18, AP13.15; but ἐν Ἰσθμῷ correctly in Hdt.9.27,81.
3. narrow ridge, of the Caucasus, between Caspian and Euxine, Arist.Mu.393b25, D.P.20.