crisis vs emergency

crisis and emergency both are nouns.

Word	Noun	Adjective	Verb	Adverb
crisis	Yes	No	No	No
emergency	Yes	No	No	No

As nouns, emergency is a hyponym of crisis; that is, emergency is a word with a more specific, narrower meaning than crisis:

crisis: a crucial stage or turning point in the course of something
emergency: a sudden unforeseen crisis (usually involving danger) that requires immediate action

Other hyponyms of crisis include exigency, pinch.

crisis (noun)	emergency (noun)
a crucial stage or turning point in the course of something	a brake operated by hand; usually operates by mechanical linkage
an unstable situation of extreme danger or difficulty	a sudden unforeseen crisis (usually involving danger) that requires immediate action
	a state in which martial law applies