isthmus

American  

[is-muhs] / ˈɪs məs /

noun

plural

isthmuses, isthmi

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 /

plural

isthmuses

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

• isthmoid
  adjective

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

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

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

The latter desert separated advanced human societies of Mesoamerica from those of North America, while the isthmus separated advanced societies of Mesoamerica from those of the Andes and Amazonia.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond

Related Words

• collar