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

Panama's Ministry of Culture said the discovery was "of great importance for Panamanian archaeology and the study of pre-Hispanic societies of the Central American isthmus," referring to the land that connects North and South America.

From Barron's ● Feb. 21, 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

The migrant route through the narrow isthmus grew exponentially in popularity in recent years with the help of organized crime in Colombia, making it an affordable, if dangerous, land route for hundreds of thousands.

From Seattle Times ● May 10, 2024

The saying goes that almost every family here on the isthmus includes a person who identifies as muxe.

From Los Angeles Times ● Jan. 11, 2024

Brannon asked, as a smile began to build on the spartan isthmus around his mouth.

From "The Great Santini" by Pat Conroy

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

The isthmuses of Panama and Suez are in our way; we cut through them!

From Celebrated Travels and Travellers Part III. The Great Explorers of the Nineteenth Century by D'Anvers, N.

Great masses of vegetation, piers, causeways, isthmuses of grass offered the illusion of growing out of the ocean bottom, linking themselves to the land, extending too late the lost coast far out into the Pacific.

From Greener Than You Think by Moore, Ward

Nay, we ought to feel some shame when we reflect that evidences in the neighborhood of both isthmuses exist of such junction having existed, in what we are pleased to designate "barbarous" ages.

From Harper's New Monthly Magazine, Vol. 1. No 1, June 1850 by Various

The substances washed down by rain-waters form by their accumulation new bars, isthmuses of deposited earth, and points of division that did not before exist.

From Personal Narrative of Travels to the Equinoctial Regions of America, During the Year 1799-1804 — Volume 2 by Humboldt, Alexander von

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