Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “guinea pig”

See all translations

guinea pig

noun [C]  /ˈɡɪn·i ˌpɪɡ/ us  
a small, furry animal with rounded ears, short legs, and no tail, often kept as a pet and for use in scientific experiments fig. A guinea pig is also a person used in a test, esp. one to discover how effective a new drug or process is: Her own son accused her of having used him as a guinea pig to test her theories about the education of children.
(Definition of guinea pig from the Cambridge Academic Content Dictionary © Cambridge University Press)
What is the pronunciation of guinea pig?
Add Cambridge dictionaries to your browser to your website

Definitions of “guinea pig” in other dictionaries

Word of the Day

cold snap

a short period of cold weather

Word of the Day

Cleavage proves divisive in Cambridge’s words of 2014

by Alastair Horne,
December 19, 2014
​​​​ Other dictionaries may choose faddish novelties as their words of the year, but here at Cambridge, we like to do something different. We look for the words that have seen sudden surges in searches over the course of the year – words that have been baffling users of English and driven them

Read More 

cinderella surgery noun

December 15, 2014
cosmetic surgery to the feet We have all heard of people having nose jobs, boob jobs and liposuction – but now a new trend growing in popularity in America: Cinderella surgery.

Read More