side effect vs outcome

side effect and outcome both are nouns.

Word	Noun	Adjective	Verb	Adverb
side effect	Yes	No	No	No
outcome	Yes	No	No	No

As nouns, outcome is a hypernym of side effect; that is, outcome is a word with a broader meaning than side effect:

side effect: any adverse and unwanted secondary effect
outcome: a phenomenon that follows and is caused by some previous phenomenon

Other hypernyms of side effect include consequence, effect, event, issue, result, upshot.

side effect (noun)	outcome (noun)
any adverse and unwanted secondary effect	something that results
a secondary and usually adverse effect of a drug or therapy	a phenomenon that follows and is caused by some previous phenomenon