mass hysteria vs hysteria

mass hysteria and hysteria both are nouns.

Word	Noun	Adjective	Verb	Adverb
mass hysteria	Yes	No	No	No
hysteria	Yes	No	No	No

As nouns, hysteria is a hypernym of mass hysteria; that is, hysteria is a word with a broader meaning than mass hysteria:

mass hysteria: a condition in which a large group of people exhibit the same state of violent mental agitation
hysteria: state of violent mental agitation

Other hypernyms of mass hysteria include craze, delirium, frenzy, fury.

mass hysteria (noun)	hysteria (noun)
a condition in which a large group of people exhibit the same state of violent mental agitation	excessive or uncontrollable fear
	neurotic disorder characterized by violent emotional outbreaks and disturbances of sensory and motor functions
	state of violent mental agitation