Hirdom or Heirdom: How To spell?

The word Hirdom is misspelled against Heirdom, a noun meaning "The state of an heir; succession by inheritance."

Word contains consecutive vowels 'EI' in between alphabets h & rdom is misspelled as 'I' as letter 'E' is phonetically ignored
Wrong Spelling:  h-i-rdom 
Correct Spelling:  h-ei-rdom 
Find more incorrect spellings of Heirdom to spell right way.