Yesternon or Yesternoon: How To spell?
The word Yesternon is misspelled against Yesternoon, a noun meaning "The noon of yesterday; the noon last past."
Yesternoon has double "oo" is mispronounced as "o"Remember double 'OO' in between the strings yestern & n which should not be misspelled with single 'O'
Wrong Spelling:  yestern-o-n  Correct Spelling:  yestern-oo-n 
Find more incorrect spellings of Yesternoon to spell right way.