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.

---

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 /

plural

isthmuses

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

• isthmoid adjective

Etymology

Origin of isthmus

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

Example Sentences

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

The Chonhar bridge hit overnight is one of just a handful of access roads to Crimea, which is linked to the Ukrainian mainland by a narrow isthmus.

From Reuters • Jun. 22, 2023

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

From "The Great Santini" by Pat Conroy

Related Words

• collar