Pianisimo or Pianissimo: How To spell?
The word Pianisimo is misspelled against Pianissimo, an adjective meaning "Very soft; -- a direction to execute a passage as softly as possible. (Abbrev. pp.)"
Pianissimo has double "ss" is mispronounced as "s"Remember double 'SS' in between the strings piani & imo which should not be misspelled with single 'S'
Wrong Spelling:  piani-s-imo  Correct Spelling:  piani-ss-imo 
Find more incorrect spellings of Pianissimo to spell right way.