sanitarium vs hospital

sanitarium and hospital both are nouns.

Word	Noun	Adjective	Verb	Adverb
sanitarium	Yes	No	No	No
hospital	Yes	No	No	No

As nouns, hospital is a hypernym of sanitarium; that is, hospital is a word with a broader meaning than sanitarium:

sanitarium: a hospital for recuperation or for the treatment of chronic diseases
hospital: a health facility where patients receive treatment

Other hypernyms of sanitarium include infirmary.

sanitarium (noun)	hospital (noun)
a hospital for recuperation or for the treatment of chronic diseases	a health facility where patients receive treatment
	a medical institution where sick or injured people are given medical or surgical care