Pronunciation: (is'mus),[key] —n., —pl.-mus•es, -miPronunciation: (-mī).[key] 1. a narrow strip of land, bordered on both sides by water, connecting two larger bodies of land.
2. Anat.,Zool.a connecting, usually narrow, part, organ, or passage, esp. when joining structures or cavities larger than itself.
3. Ichthyol.the narrow fleshy area between the sides of the lower jaw of a fish.