Isochym or Isocheim: How To spell?

The word Isochym is misspelled against Isocheim, a noun meaning "A line connecting places on the earth having the same mean winter temperature. Cf. Isothere."

Word contains consecutive vowels 'EI' in between alphabets isoch & m is misspelled as 'Y'
Wrong Spelling:  isoch-y-m 
Correct Spelling:  isoch-ei-m 
Find more incorrect spellings of Isocheim to spell right way.