diarrhea vs diarrhoea

diarrhea and diarrhoea both are nouns.

Word	Noun	Adjective	Verb	Adverb
diarrhea	Yes	No	No	No
diarrhoea	Yes	No	No	No

As nouns, diarrhea and diarrhoea are synonyms defined as:

diarrhea and diarrhoea: frequent and watery bowel movements; can be a symptom of infection or food poisoning or colitis or a gastrointestinal tumor

Other synonyms of diarrhea include looseness, looseness of the bowels.

diarrhea (noun)	diarrhoea (noun)
frequent and watery bowel movements; can be a symptom of infection or food poisoning or colitis or a gastrointestinal tumor	frequent and watery bowel movements; can be a symptom of infection or food poisoning or colitis or a gastrointestinal tumor