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.

---

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

---

isthmus Scientific  

/ ĭs′məs /

• isthmuses
  plural

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

---

isthmus Cultural  

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

---

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

Perhaps to that end, López Obrador announced Friday that Mexico plans to extend a cargo train line that spans a narrow isthmus its the south to the Guatemalan border.

From Seattle Times ● May 17, 2024

“Even though I am not muxe from the isthmus, for me the word implies respect and tolerance,” said Lía Maritza Sánchez, 51, an L.A.

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

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 Ward Moore

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

During a long interval of rest, from the length of time allowed to the above processes, the tendency would often prove effective, both in forming, by accumulation of matter, isthmuses, and in keeping open channels.

From More Letters of Charles Darwin — Volume 2 by Sir Francis Darwin

They made islands and peninsulas and isthmuses of green that were odd and freaky.

From A Little Girl in Old New York by Amanda Minnie Douglas

Related Words

• collar