rubeola vs contagion

rubeola and contagion both are nouns.

Word	Noun	Adjective	Verb	Adverb
rubeola	Yes	No	No	No
contagion	Yes	No	No	No

As nouns, contagion is a hypernym of rubeola; that is, contagion is a word with a broader meaning than rubeola:

rubeola: an acute and highly contagious viral disease marked by distinct red spots followed by a rash; occurs primarily in children
contagion: any disease easily transmitted by contact

Other hypernyms of rubeola include contagious disease.

rubeola (noun)	contagion (noun)
an acute and highly contagious viral disease marked by distinct red spots followed by a rash; occurs primarily in children	the communication of an attitude or emotional state among a number of people
	an incident in which an infectious disease is transmitted
	any disease easily transmitted by contact