placebo effect vs event

placebo effect and event both are nouns.

Word	Noun	Adjective	Verb	Adverb
placebo effect	Yes	No	No	No
event	Yes	No	No	No

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

placebo effect: any effect that seems to be a consequence of administering a placebo; the change is usually beneficial and is assumed result from the person's faith in the treatment or preconceptions about what the experimental drug was supposed to do; pharmacologists were the first to talk about placebo effects but now the idea has been generalized to many situations having nothing to do with drugs
event: a phenomenon that follows and is caused by some previous phenomenon

Other hypernyms of placebo effect include consequence, effect, issue, outcome, result, upshot.

placebo effect (noun)	event (noun)
any effect that seems to be a consequence of administering a placebo; the change is usually beneficial and is assumed result from the person's faith in the treatment or preconceptions about what the experimental drug was supposed to do; pharmacologists were the first to talk about placebo effects but now the idea has been generalized to many situations having nothing to do with drugs	something that happens at a given place and time
	a phenomenon located at a single point in space-time; the fundamental observational entity in relativity theory
	a phenomenon that follows and is caused by some previous phenomenon
	a special set of circumstances