epidemic roseola vs rubella

epidemic roseola and rubella both are nouns.

Word	Noun	Adjective	Verb	Adverb
epidemic roseola	Yes	No	No	No
rubella	Yes	No	No	No

As nouns, epidemic roseola and rubella are synonyms defined as:

epidemic roseola and rubella: a contagious viral disease that is a milder form of measles lasting three or four days; can be damaging to a fetus during the first trimester

Other synonyms of epidemic roseola include German measles, three-day measles.

epidemic roseola (noun)	rubella (noun)
a contagious viral disease that is a milder form of measles lasting three or four days; can be damaging to a fetus during the first trimester	a contagious viral disease that is a milder form of measles lasting three or four days; can be damaging to a fetus during the first trimester