menses vs menorrhagia

menses and menorrhagia both are nouns.

Word	Noun	Adjective	Verb	Adverb
menses	Yes	No	No	No
menorrhagia	Yes	No	No	No

As nouns, menorrhagia is a hyponym of menses; that is, menorrhagia is a word with a more specific, narrower meaning than menses:

menses: the monthly discharge of blood from the uterus of nonpregnant women from puberty to menopause
menorrhagia: abnormally heavy or prolonged menstruation; can be a symptom of uterine tumors and can lead to anemia if prolonged

Other hyponyms of menses include hypermenorrhea, oligomenorrhea.

menses (noun)	menorrhagia (noun)
the monthly discharge of blood from the uterus of nonpregnant women from puberty to menopause	abnormally heavy or prolonged menstruation; can be a symptom of uterine tumors and can lead to anemia if prolonged