Expresion or Expression: How To spell?
The word Expresion is misspelled against Expression, a noun meaning "A form of words in which an idea or sentiment is conveyed; a mode of speech; a phrase; as, a common expression; an odd expression."
Expression has double "ss" is mispronounced as "s"Remember double 'SS' in between the strings expre & ion which should not be misspelled with single 'S'
Wrong Spelling:  expre-s-ion  Correct Spelling:  expre-ss-ion 
Find more incorrect spellings of Expression to spell right way.