ISTHMUS is a playable word

isthmus Scrabble® Dictionary

noun
pl. isthmuses or isthmi
a strip of land connecting two larger land masses
83 Playable Words can be made from "ISTHMUS"
   2-Letter Words (13 found)
   3-Letter Words (20 found)
   6-Letter Words (2 found)
   7-Letter Words (1 found)