guinea pig
noun
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
Rabbits can transmit diseases to guinea pigs and may bully them.
—
Maria Azzurra Volpe, MSNBC Newsweek, 22 Aug. 2025
After 1,145 adoptions already this month, there are currently 854 adoptable animals — 369 dogs, 19 puppies, 165 cats, 106 kittens, 89 guinea pigs and 54 reptiles — in the organization’s care.
—Caleb Lunetta, San Diego Union-Tribune, 21 Aug. 2025
Zoo shares rules for animal donations The zoo accepts guinea pigs, chickens, and rabbits on weekdays.
—Taylor Ardrey, USA Today, 4 Aug. 2025
The French biochemist and New York Times bestselling author has offered herself up as a guinea pig—wearing a continuous glucose monitor and tracking how different foods spike her blood sugar, which in turn affects mood, brain fog, nerve function, and more—and sharing the quantifiable data online.
—Margaux Anbouba, Vogue, 29 July 2025
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Maria Azzurra Volpe, MSNBC Newsweek, 22 Aug. 2025
After 1,145 adoptions already this month, there are currently 854 adoptable animals — 369 dogs, 19 puppies, 165 cats, 106 kittens, 89 guinea pigs and 54 reptiles — in the organization’s care.
—Caleb Lunetta, San Diego Union-Tribune, 21 Aug. 2025
Zoo shares rules for animal donations The zoo accepts guinea pigs, chickens, and rabbits on weekdays.
—Taylor Ardrey, USA Today, 4 Aug. 2025
The French biochemist and New York Times bestselling author has offered herself up as a guinea pig—wearing a continuous glucose monitor and tracking how different foods spike her blood sugar, which in turn affects mood, brain fog, nerve function, and more—and sharing the quantifiable data online.
—Margaux Anbouba, Vogue, 29 July 2025
See All Example Sentences for guinea pig
Cite this Entry
“Guinea pig.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/guinea%20pig. Accessed 3 Sep. 2025.
Copy CitationMedical Definition
guinea pig
noun
guin·ea pig
ˈgin-ē-ˌ 
: 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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