Perisad or Perissad: How To spell?
The word Perisad is misspelled against Perissad, an adjective meaning "Odd; not even; -- said of elementary substances and of radicals whose valence is not divisible by two without a remainder. Contrasted with artiad."
Perissad has double "ss" is mispronounced as "s"Remember double 'SS' in between the strings peri & ad which should not be misspelled with single 'S'
Wrong Spelling:  peri-s-ad  Correct Spelling:  peri-ss-ad 
Find more wrongly spelled words of Perissad to spell it well.