Definition of piranha in US English:



  • A deep-bodied South American freshwater fish that typically lives in schools and has very sharp teeth that are used to tear flesh from prey. It has a reputation as a fearsome predator.

    Serrasalmus and other genera, family Characidae: several species, including the red (or red-bellied) piranha (S. natterei)

    • ‘Two well-known fish with multiple rows of teeth are piranhas and sharks.’
    • ‘You become fish bait to the school of piranhas circling around.’
    • ‘She glanced across at her large fish tank, where two piranhas swam back and forth.’
    • ‘Some items are curios, such as a necklace of peccary teeth and a piranha jaw fashioned into a cutting tool.’
    • ‘I would rather throw myself to piranhas than have that reputation.’


Mid 18th century: via Portuguese from Tupi pirá ‘fish’ + sainha ‘tooth’.