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

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Etymology

Origin of isthmus

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

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

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

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

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

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 Alexander von Humboldt

The pseudospores of Rœstelia are produced in strings or chaplets, as in Æcidium, with this difference, that instead of being contiguous they are separated by narrow isthmuses.

From Fungi: Their Nature and Uses by M. C. (Mordecai Cubitt) Cooke

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