guinea pig


Definition of guinea pig 

1 : a small stout-bodied short-eared tailless domesticated rodent (Cavia porcellus) of South American origin often kept as a pet and widely used in biological research

called also cavy

2 : a subject of research, experimentation, or testing

Examples of guinea pig in a Sentence

He volunteered to act as a guinea pig in the experiment.

Recent Examples on the Web

Human guinea pigs are now driving sensor- and camera-laden Teslas, Volvos, and Range Rovers around the Boston area. Aarian Marshall, WIRED, "Tesla's Favorite Autopilot Safety Stat Just Doesn't Hold Up," 4 May 2018 Some of the animals commonly used include non-human primates, guinea pigs, rabbits and pigs. Dana Burke, Houston Chronicle, "See the numbers: Animal research reported in the Houston area," 26 Apr. 2018 Other rooms will be added for small mammals like rabbits and guinea pigs, grooming, taking photos and prepping food. Kate Talerico, The Courier-Journal, "City breaks ground on 'no kill' animal shelter slated to open in mid-2019," 5 July 2018 The young, often a pair, are born during hibernation and are small enough to hold in your hand, about half the size of a guinea pig and just 6-8 ounces. Tom Stienstra, San Francisco Chronicle, "It’s nature’s way, caught on camera," 27 May 2018 The inn has no pet-type restrictions, so pack up the bird, guinea pig, and hamster, too. Laurie Wilson,, "These hotels are the cat’s meow," 25 Apr. 2018 She will also be mourned by her beloved pets, her German Shepherd Sophia and her guinea pig Marvin. Hartford Courant,, "Ashley L. Rakus," 10 July 2018 This makes drivers, and anyone encountering these cars on the road, guinea pigs who are helping to train the artificial intelligence Tesla ultimately hopes to use for a fully autonomous driving system. Christopher Mims, WSJ, "In Self-Driving-Car Road Test, We Are the Guinea Pigs," 13 May 2018 The 641 guinea pigs in the six-week test program were mailed postcards alerting them that county employees would be looking in their recycling bins on Thursdays, the subdivision’s usual collection day for recyclables. Stephen Hudak,, "Orange County peering into recycling bins to check for no-nos like greasy pizza boxes, plastic bags," 28 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'guinea pig.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of guinea pig

1664, in the meaning defined at sense 1

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Last Updated

11 Sep 2018

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Time Traveler for guinea pig

The first known use of guinea pig was in 1664

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More Definitions for guinea pig

guinea pig


English Language Learners Definition of guinea pig

: a small animal that is often kept as a pet

: a person or thing used for testing something

guinea pig


Kids Definition of guinea pig

: a small stocky South American animal that is a rodent with short ears and a very short tail and is often kept as a pet

guinea pig

guin·ea pig | \ ˈgin-ē-ˌ \

Medical Definition of guinea pig 

: a small stout-bodied short-eared nearly tailless domesticated rodent of the genus Cavia (C. cobaya) often kept as a pet and widely used in biological research

called also cavy

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