piranha

American  

[pi-rah-nuh, -ra-, -nyuh] / pɪˈrɑ nə, -ˈræ-, -nyə /

noun

plural

piranhas,

plural

piranha

1. 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.

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piranha British  

/ pɪˈrɑːnjə /

noun

1. any of various small freshwater voracious fishes of the genus Serrasalmus and related genera, of tropical America, having strong jaws and sharp teeth: family Characidae (characins)

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Etymology

Origin of piranha

1865–70; < Portuguese < Tupi

Explanation

A piranha is a fish with famously sharp teeth. Don't go swimming in certain South American rivers if you want to avoid piranhas! These freshwater fish are terrifyingly described as "voraciously carnivorous," meaning they eat meat with great enthusiasm. Humans aren't often bitten by piranhas, but it does happen in some parts of South America. You also can't buy a piranha as a pet in many parts of the world — and if you do, it's best not to get two of them, since the weaker fish is often killed by the stronger one.

Example Sentences

TalkTV broadcaster Mark Dolan noted how the man known as the "piranha of the airwaves" had "reinvented the phone-in format in the UK - with stunning success".

From BBC • Dec. 1, 2025

As Richard, the deceased father of Jenna Ortega’s Astrid Deetz, Santiago Cabrera got a combination of prosthetics and makeup for the puppet piranha fish biting at his face, neck and body.

From Los Angeles Times • Sep. 12, 2024

That set off a competitive scramble among other Mexican states, like feeding time at a piranha tank.

From Seattle Times • Feb. 24, 2023

White once said her character Sue Ann Nivens in “The Mary Tyler Moore Show” could be “icky-sweet” but was “really a piranha type.”

From Washington Times • Dec. 31, 2021

It can stand in for anything—a stuffed piranha, existentialism, the Monroe Doctrine, or buttered toast.

From "Woe Is I" by Patricia T. O'Conner