Isth″mus (?; 277), n.; pl.Isthmuses (#). [L. isthmus, Gr. ισθμὄσ a neck, a neck of land between two seas, an isthmus, especially the Isthmus of Corinth; prob. from the root of ιἔναι to go; cf. Icel. eið isthmus. See Issue.] (Geog.) A neck or narrow slip of land by which two continents are connected, or by which a peninsula is united to the mainland; as, the Isthmus of Panama; the Isthmus of Suez, etc.
Isthmus of the fauces. (Anat.) See Fauces.