Lewis & Short

Isthmus or -os, i, m., = Ἰσθμός,

  1. I. a strip of land between two seas, an isthmus, Mel. 1, 18; 2, 2.
    1. B. Esp., the Isthmus of Corinth, where the Isthmian games were celebrated, Caes. B. C. 3, 55, 2; Liv. 45, 28, 2 sq.; Plin. 4, 1, 5, § 12; Cic. Fat. 4, 7; Suet. Ner. 19; Mel. 2, 3; Ov. M. 7, 406.
    2. C. Transf., poet., a strait, viz., the Dardanelles, Prop. 3, 21, 1 (4, 22, 2).
  2. II. Derivv.
    1. A. Isthmĭus, a, um, adj., = Ἴσθμιος, of or belonging to the Isthmus, Isthmian: ludi, Liv. 33, 32: labor, Hor. C. 4, 3, 3: Dione, i. e. Venus, who had a temple at Corinth, Stat. S. 2, 7, 2.
      Esp. freq. subst.: Isthmĭa, ōrum, n., = τὰ Ἴσθμια, the Isthmian games, celebrated every five years at the Isthmus of Corinth, the victors in which received a pine garland, Liv. 33, 32; Curt. 4, 5, 8; cf. Plin. 15, 10, 9, § 36.
    2. B. Isthmĭăcus (Isth-mĭcus), a, um, adj., of or belonging to the Isthmus, Isthmian: harena, Stat. Th. 6, 557: litus, Claud. IV. Cons. Hon. 463: coloni, i. e. Syracusans (as a colony of Corinth), Sil. 14, 341; cf. favillae, Stat. S. 2, 2, 68.
      Form Isthmicus, Mel. 2, 3; Val. Max. 4, 8, 5.