[is-muh s]

noun, plural isth·mus·es, isth·mi [is-mahy] /ˈɪs maɪ/.

a narrow strip of land, bordered on both sides by water, connecting two larger bodies of land.
Anatomy, Zoology. a connecting, usually narrow, part, organ, or passage, especially when joining structures or cavities larger than itself.
Ichthyology. the narrow fleshy area between the sides of the lower jaw of a fish.

Origin of isthmus

1545–55; < Latin < Greek isthmós neck (of land)
Related formsisth·moid, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for isthmus

collar, strait, cape, cervix, scruff, nape, isthmus

Examples from the Web for isthmus

Contemporary Examples of isthmus

  • Is it really possible that we were once so wrapped around that isthmus?

    The Daily Beast logo
    The Frum Flap

    Christopher Buckley

    March 27, 2010

  • The only thing it rhymes with is isthmus, and that but loosely.

    The Daily Beast logo
    A Mark Twain Christmas Story

    The Daily Beast

    December 24, 2009

Historical Examples of isthmus

  • They were on a peninsula, as it were, while the soldiers were securing the isthmus.

  • I returned stoutly; for I had, of course, sunk the Isthmus of Panama beneath the sea.

    Green Mansions

    W. H. Hudson

  • This part, like an isthmus, was called "Heaven's Floating Bridge."

    Japanese Fairy World

    William Elliot Griffis

  • We can get all the women we want, and of our own kind without crossing the Isthmus.

    Sir Henry Morgan, Buccaneer

    Cyrus Townsend Brady

  • They landed on the mainland, and, crossing the isthmus, made for Panama.

    Plotting in Pirate Seas

    Francis Rolt-Wheeler

British Dictionary definitions for isthmus


noun plural -muses or -mi (-maɪ)

a narrow strip of land connecting two relatively large land areas
  1. a narrow band of tissue connecting two larger parts of a structure
  2. a narrow passage connecting two cavities
Derived Formsisthmoid, adjective

Word Origin for isthmus

C16: from Latin, from Greek isthmos
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for isthmus

1550s, from Latin isthmus, from Greek isthmos "narrow passage, narrow neck of land," especially that of Corinth, of unknown origin, perhaps from eimi "to go" + suffix -thmo (cf. ithma "a step, movement").

Online Etymology Dictionary, © 2010 Douglas Harper

isthmus in Medicine



n. pl. isth•mus•es

A constriction or narrow passage connecting two larger parts of an organ or other anatomical structure.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

isthmus in Science



Plural isthmuses isthmi (ĭsmī′)

A narrow strip of land connecting two larger masses of land.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

isthmus in Culture



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

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.