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Definition of guinea pig
guinea pig
Plural:guinea pigs
• noun
1
A tailless, domesticated South American rodent (Cavia porcellus) belonging to the cavy family, widely kept as a pet and historically used in biological research.
Example
"The children were thrilled to adopt a fluffy Guinea pig from the local animal shelter."
2
A person or thing used as a subject for an experiment, trial, or test.
Example
"The developer asked her colleagues to act as Guinea pigs for the beta version of the new software application."
Synonyms
View all synonyms for guinea pig• Nearby Words
Usage Trend
Historical frequency of usage in published text.
180019102020
Data source: Google Books Ngram Viewer
Cite this Entry
Wordmom. (2026). Definition of Guinea pig. In Wordmom Dictionary. Retrieved Oct 17, 2026, from https://wordmom.com/dictionary/guinea%20pig