<p><strong>Noun</strong></p><ul><li>plural isthmuses, isthmi</li><li>a narrow strip of land, bordered on both sides by water, connecting two larger bodies of land</li><li>Anatomy, Zoology: a connecting, usually narrow, part, organ, or passage, especially when joining structures or cavities larger than itself</li><li>Ichthyology: the narrow fleshy area between the sides of the lower jaw of a fish</li></ul>