Semiianual or Semiiannual: How To spell?
The word Semiianual is misspelled against Semiiannual, an adjective meaning "Half-yearly."
Semiiannual has double "nn" is mispronounced as "n"Remember double 'NN' in between the strings semiia & ual which should not be misspelled with single 'N'
Wrong Spelling:  semiia-n-ual  Correct Spelling:  semiia-nn-ual 
Check more misspelled words of Semiiannual to spell it correct.