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
An animal rescue group in northwest Indiana is helping care for dozens of guinea pigs, many of which are pregnant, after they were rescued from what police said was a squalid home on Tuesday morning.
—
Todd Feurer, CBS News, 17 June 2026
My twin sister, 32, and mom, 72, have tried nearly as many options—and have become my unofficial product-testing guinea pigs.
—Sophie Wirt, InStyle, 14 June 2026
In 2018, researchers showed that an mRNA vaccine provided 100% protection against the Zaire species of Ebola in guinea pigs.
—Jonathan Lambert, NPR, 4 June 2026
The program has expanded to include guinea pigs, chickens, doves, goats, turtles and rabbits.
—ABC News, 31 May 2026
See All Example Sentences for guinea pig
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Todd Feurer, CBS News, 17 June 2026
My twin sister, 32, and mom, 72, have tried nearly as many options—and have become my unofficial product-testing guinea pigs.
—Sophie Wirt, InStyle, 14 June 2026
In 2018, researchers showed that an mRNA vaccine provided 100% protection against the Zaire species of Ebola in guinea pigs.
—Jonathan Lambert, NPR, 4 June 2026
The program has expanded to include guinea pigs, chickens, doves, goats, turtles and rabbits.
—ABC News, 31 May 2026
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 23 Jun. 2026.
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. porcellus) often kept as a pet and widely used in biological research
called also cavy
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