Dysentery, amebic: Dysentery (inflammation of the intestine) with ulcers in the colon due to infection with an ameba (Entamoeba histolytica). This single-celled parasite is transmitted to humans via contaminated water and food. Amebic dysentery can be accompanied by amebic infection of the liver and other organs. "Ameba" is from the Greek "amoibe" meaning "change" because amebae constantly change shape. "Dysentery" is composed of the Greek "dys-" meaning "abnormal or painful" + "enteron" meaning "intestine" = abnormal or painful intestine.