Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “guinea pig”

guinea pig

noun [C]     /ˈɡɪniˌpɪɡ/
ANIMAL a small animal with fur and no tail that people sometimes keep as a petRodents and similar animals
PERSON informal someone who is used in a test for something such as a new medicine or productTesting, checking and experimenting
(Definition of guinea pig noun from the Cambridge Learner's Dictionary © Cambridge University Press)

Definitions of “guinea pig” in other dictionaries

Word of the Day

altruistic

showing a wish to help or bring advantages to others, even if it results in disadvantage for yourself

Word of the Day

Blog

Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More