any of several small South American freshwater fishes of the genus Serrasalmus that eat other fish and sometimes plants but occasionally also attack humans and other large animals that enter the water.
pi·ra·nha also pi·ra·ña (pĭ-rän'yə, -rān'yə, -rä'nə, -rān'ə) n. Any of several tropical American freshwater fishes of the genus Serrasalmus that are voraciously carnivorous and often attack and destroy living animals. Also called caribe.
[Portuguese, from Tupi : pirá, fish + ánha, to cut.]