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guinea pig

American  

noun

  • guinea pigs
    plural
  1. a short-eared, tailless rodent of the genus Cavia, usually white, black, and tawny, commonly regarded as the domesticated form of one of the South American wild species of cavy: often used in scientific experiments or kept as a pet.

  2. Informal. the subject of any sort of experiment.

    I've volunteered as a guinea pig in several clinical trials.


guinea pig British  

noun

  1. a domesticated cavy, probably descended from Cavia porcellus, commonly kept as a pet and used in scientific experiments

  2. a person or thing used for experimentation

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Noun Inflected Forms


Etymology

Origin of guinea pig

First recorded in 1655–65


Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

At times, this makes the humble viewer feel a bit like a guinea pig in a focus group; the audience’s reactions are integral to measuring the film’s success.

From Salon ● Sep. 19, 2026

"I wouldn't want to be the first guinea pig," as "it's not so easy to have everything just smooth" like Apple has managed to do with its laptops.

From Barron's ● Jun. 1, 2026

His three-year-old guinea pig, Remington, had surgery for a bladder stone.

From BBC ● Apr. 21, 2026

As he buttoned up a professional baseball uniform for the first time in his life, he understood that he was becoming the guinea pig in an experiment that has the whole industry watching.

From The Wall Street Journal ● Nov. 25, 2025

“I can be two things! Besides. My cousin’s wife on my mother’s father’s side is a guinea pig princess. When I tell them all about this—humans.”

From "The Way to Rio Luna" by Zoraida Cordova

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