amenorrhea vs amenorrhoea

amenorrhea and amenorrhoea both are nouns.

Word	Noun	Adjective	Verb	Adverb
amenorrhea	Yes	No	No	No
amenorrhoea	Yes	No	No	No

As nouns, amenorrhea and amenorrhoea are synonyms defined as:

amenorrhea and amenorrhoea: absence or suppression of normal menstrual flow

Other synonyms of amenorrhea include amenia.

amenorrhea (noun)	amenorrhoea (noun)
absence or suppression of normal menstrual flow	absence or suppression of normal menstrual flow