Isthmus

An isthmus is a narrow strip of land connecting two larger land areas, usually with water on either side

Canals are often built across isthmuses, where they may be a particularly advantageous short cut for marine transport.

The '' The Panama Canal'' crosses the Isthmus of Panama  connecting the North Atlantic and Pacific Oceans

The ''Suez Canal'' connects the Mediterranean Sea and the Indian Ocean cutting across the western side of an isthmus formed by the Sinai Peninsula