Other spellings (UK) diarrhoea Pronunciation (UK) IPA (key): /ˌdaɪ.əˈriː.ə/ Audio (US)(file) Noun Singular diarrhea Plural diarrheas (uncountable) Diarrhea is an illness where the person's poop or feces are soft like water.Wikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads