1
: a narrow strip of land connecting two larger land areas
2
: a narrow anatomical part or passage connecting two larger structures or cavities
Examples of isthmus in a Sentence
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The challenging cultural and historical realities that have shaped and scarred the Central American isthmus have impacted each country in the region uniquely, with decades of stability surely one of the most important factors in Costa Rica's rise among travelers.
—
Carley Rojas Ávila, Forbes.com, 26 June 2025
But planes used to drop 150 million flies a week over the isthmus in Mexico during the first eradication campaign in the 1980s.
—Sarah Zhang, The Atlantic, 27 May 2025
Panama Panama has long been a haven for expats, from mountain town Boquete to beach town Bocas del Toro to bustling Panama City, there’s truly something to suit everyone in this diverse isthmus.
—Kathleen Peddicord, Forbes.com, 6 June 2025
Even after screwworms began creeping up the tail of the funnel recently, the anti-screwworm campaign had one last good chance of stopping them at a narrow isthmus in southern Mexico—after which the funnel grows dramatically wider.
—Sarah Zhang, The Atlantic, 27 May 2025
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Carley Rojas Ávila, Forbes.com, 26 June 2025
But planes used to drop 150 million flies a week over the isthmus in Mexico during the first eradication campaign in the 1980s.
—Sarah Zhang, The Atlantic, 27 May 2025
Panama Panama has long been a haven for expats, from mountain town Boquete to beach town Bocas del Toro to bustling Panama City, there’s truly something to suit everyone in this diverse isthmus.
—Kathleen Peddicord, Forbes.com, 6 June 2025
Even after screwworms began creeping up the tail of the funnel recently, the anti-screwworm campaign had one last good chance of stopping them at a narrow isthmus in southern Mexico—after which the funnel grows dramatically wider.
—Sarah Zhang, The Atlantic, 27 May 2025
See All Example Sentences for isthmus
Cite this Entry
“Isthmus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/isthmus. Accessed 20 Jul. 2025.
Copy CitationKids Definition
isthmus
noun
isth·mus
ˈis-məs 
: a narrow strip of land connecting two larger land areas
Medical Definition
isthmus
noun
isth·mus
ˈis-məs
: a contracted anatomical part or passage connecting two larger structures or cavities: as
a
: an embryonic constriction separating the midbrain from the hindbrain
b
: the lower portion of the uterine corpus
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