Pasus or Passus: How To spell?
The word Pasus is misspelled against Passus, a noun meaning "A division or part; a canto; as, the passus of Piers Plowman. See 2d Fit."
Passus has double "ss" is mispronounced as "s"Remember double 'SS' in between the strings pa & us which should not be misspelled with single 'S'
Wrong Spelling:  pa-s-us  Correct Spelling:  pa-ss-us 
Check more misspelled words of Passus to spell it correct.