oligomenorrhea vs catamenia

oligomenorrhea and catamenia both are nouns.

Word	Noun	Adjective	Verb	Adverb
oligomenorrhea	Yes	No	No	No
catamenia	Yes	No	No	No

As nouns, catamenia is a hypernym of oligomenorrhea; that is, catamenia is a word with a broader meaning than oligomenorrhea:

oligomenorrhea: abnormally light or infrequent menstruation
catamenia: the monthly discharge of blood from the uterus of nonpregnant women from puberty to menopause

Other hypernyms of oligomenorrhea include flow, menses, menstruation, menstruum, period.

oligomenorrhea (noun)	catamenia (noun)
abnormally light or infrequent menstruation	the monthly discharge of blood from the uterus of nonpregnant women from puberty to menopause