Ĭsth'mus, n.

(ĭs'mus, or ĭst'mus, 100), n.; pl. ĬSTH'-MUS-ES (ĭs'mus-ez, or ĭst'mus-ez). [Lat. isthmus, Gr. ἰσθμός, a neck, a neck of land between two seas, an isthmus, especially the Isthmus of Corinth.] (Geog.) A neck or narrow slip of land by which two continents are connected, or by which a peninsula is united to the main land; as, the Isthmus of Darien; the Isthmus of Suez.}