Definition of isthmus in English:


Line breaks: isth|mus
Pronunciation: /ˈɪsθməs
, ˈɪstməs
, ˈɪsməs

noun (plural isthmuses)

  • 1A narrow strip of land with sea on either side, forming a link between two larger areas of land.
    More example sentences
    • Land routes are really old, especially through isthmuses.
    • The British arrived almost a century ago to build the railroad that slices across the isthmus, linking the Gulf of Mexico to the Pacific Ocean.
    • Only one study to date has used calibration points from the fossil record to estimate the divergence of sister species distributed on both sides of the isthmus.
  • 2 (plural isthmi) Anatomy A narrow organ, passage, or piece of tissue connecting two larger parts.
    More example sentences
    • Thoracic aortic injuries most often occur at the aortic isthmus in the majority of the cases.
    • It has 2 lobes, called the right lobe and the left lobe, joined by a narrow isthmus.
    • The cervix forms the lower third, connected by a narrow isthmus to the main muscular body of the uterus.


mid 16th century: via Latin from Greek isthmos.

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