-rrhoea Also -rrhoeic, and -rrhoeal (US -rrhea, -rhea, -rrheic, and -rrheal).
[Greek rhoia, flow, flux.]
Diarrhoea (Greek dia, through) is a condition in which faeces are discharged from the bowels frequently and in a liquid form; gonorrhoea (Greek gonos, semen) is a venereal disease involving inflammatory discharge from the urethra or vagina; amenorrhoea (Greek a-, without, plus mēn, month) is an abnormal absence of menstruation; seborrhoea is excessive discharge of sebum from the sebaceous glands.
The standard US spelling of the ending is -rrhea (diarrhea, seborrhea); it is occasionally spelled with only one r (diarhea, amenorhea).
Adjectives are formed in -rrhoeic (seborrhoeic, diarrhoeic), or -rrhoeal (gonorrhoeal, amenorrhoeal).