isthmus

American  

[is-muhs] / ˈɪs məs /

noun

• isthmuses,
  plural
• isthmi
  plural

1. a narrow strip of land, bordered on both sides by water, connecting two larger bodies of land.

2. Anatomy, Zoology. a connecting, usually narrow, part, organ, or passage, especially when joining structures or cavities larger than itself.

3. Ichthyology. the narrow fleshy area between the sides of the lower jaw of a fish.

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isthmus British  

/ ˈɪsməs /

noun

1. a narrow strip of land connecting two relatively large land areas

2. anatomy

   1. a narrow band of tissue connecting two larger parts of a structure

   2. a narrow passage connecting two cavities

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isthmus Scientific  

/ ĭs′məs /

• isthmuses
  plural

1. A narrow strip of land connecting two larger masses of land.

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isthmus Cultural  

1. A narrow strip of land that connects two larger bodies of land and has water on both sides.

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Other Word Forms

Derived Forms

• isthmoid
  adjective

Inflected Forms

Nouns

• isthmi
  plural
• isthmuses
  plural

Etymology

Origin of isthmus

1545–55; < Latin < Greek isthmós neck (of land)

Explanation

An isthmus is a land bridge, a narrow strip of land that stretches across a body of water to connect two larger land masses. The Greek isthmos means "neck," so you can see how isthmus came to mean the connecting strip between land masses. If you look at an example, say the Isthmus of Panama, you can see how that neck-like bit of land separates the Caribbean Sea from the North Pacific Ocean as it connects North and South America. Think of an isthmus as kind of like a turkey neck that connects the bird's body and head (at least until Thanksgiving).

Example Sentences

See Examples For:

isthmus isthmuses

Roosevelt was intrigued by the military and commercial possibilities of a canal across the isthmus, cutting 8,000 miles off a New York-San Francisco voyage.

From Barron's ● Jan. 18, 2026

Paterson persuaded the Scottish parliament to establish a new enterprise based on England’s East India Company to found a Scottish colony on the narrow isthmus joining North and South America.

From The Wall Street Journal ● Nov. 30, 2025

Many gay and trans people in Mexico City and elsewhere call themselves muxes — though community leaders here, concerned about cultural appropriation, say only Zapotec people from the isthmus can qualify.

From Los Angeles Times ● Jan. 11, 2024

It is known as the 'gap' on Panama's Darien isthmus because it is the only missing section, running about 60 miles, on the Pan-American highway that stretches from Alaska to Argentina.

From Reuters ● Jul. 22, 2023

Torchbearers, dressed in traditional Montenegrin costume—loose-fitting white pants and shirt and a colorful green vest—lined the isthmus leading out to a well-appointed hotel called the Maestral, which had once been a thirteenth-century medieval fort.

From "Endgame" by Frank Brady

The Crimean Peninsula extends south from Ukraine’s mainland, with road connections on two isthmuses, one of which is less than 1 mile wide, and by a bridge from a narrow spit.

From Washington Times ● Jul. 17, 2023

In the first place it was agreed that any canal to be constructed over any of the isthmuses was to be absolutely neutral, in time of war as well as of peace.

From The Path of Empire; a chronicle of the United States as a world power by Carl Russell Fish

These two isthmuses in the eastern and western hemispheres have some obvious features in common.

From The Panama Canal A history and description of the enterprise by J. Saxon Mills

M. de Lesseps was elected to the Academy in 1885, when M. Renan said he had been born to pierce isthmuses, and that antiquity would have made him a god.

From The West Indies and the Spanish Main by James Rodway

Marine isthmuses, cutting of, 517; its difficulties, 518; sometimes done by nature, 519.

From Man and Nature or, Physical Geography as Modified by Human Action by George P. Marsh

Related Words

• collar