menstrual flow vs menorrhea

menstrual flow and menorrhea both are nouns.

Word	Noun	Adjective	Verb	Adverb
menstrual flow	Yes	No	No	No
menorrhea	Yes	No	No	No

As nouns, menstrual flow and menorrhea are synonyms defined as:

menstrual flow and menorrhea: flow of blood from the uterus; occurs at roughly monthly intervals during a woman's reproductive years

Other synonyms of menstrual flow include menstrual blood.

menstrual flow (noun)	menorrhea (noun)
flow of blood from the uterus; occurs at roughly monthly intervals during a woman's reproductive years	flow of blood from the uterus; occurs at roughly monthly intervals during a woman's reproductive years