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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 pet Rodents and similar animals
PERSON informal someone who is used in a test for something such as a new medicine or product Testing, checking and experimenting
(Definition of guinea pig noun from the Cambridge Learner's Dictionary © Cambridge University Press)

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