isthmuses

noun pl. isthmuses or isthmi

1. a narrow strip of land having water at each side and connecting two larger bodies of land
2. Anat.
   1. a narrow strip of tissue connecting two larger parts of an organ: the isthmus of the thyroid
   2. a narrow passage between two larger cavities: the isthmus of the fallopian tubes

Origin: L < Gr isthmos, a neck, narrow passage, isthmus