1. a narrow isthmus between the Gulf of Corinth and the Saronic Gulf; a canal crosses the isthmus so that navigation is possible between the gulfs;
WordNet (r) 3.0 (2006):
Isthmus of Corinth
n 1: a narrow isthmus between the Gulf of Corinth and the
Saronic Gulf; a canal crosses the isthmus so that
navigation is possible between the gulfs