An isthmus is a narrow strip of land, bordered on two sides by water, and connects two larger land masses. The term is pronounced “IS-mus” with a silent th. The plural form can either be isthmuses or isthmi.
- the Isthmus of Suez: the isthmus between Africa and Asia, in Egypt where the Suez Canal is located
- the Isthmus of Kra, which joins the Malay Peninsula with mainland Asia
- The first isthmus so-named is the Isthmus of Corinth, in Greece
- the Isthmus of Avalon, Canada: separate the main island of Newfoundland from the Peninsula of Avalon (where the capital, St. John's, is).
Isthmuses are the duals of straits. That is, while isthmuses lie between two bodies of water and joins two larger land masses, straits lie between two land masses and connects two larger bodies of water.