Precesion or Precession: How To spell?
The word Precesion is misspelled against Precession, meaning "The act of going forward."
Precession has double "ss" is mispronounced as "s"Remember double 'SS' in between the strings prece & ion which should not be misspelled with single 'S'
Wrong Spelling:  prece-s-ion  Correct Spelling:  prece-ss-ion 
Find more incorrect spellings of Precession to spell right way.