Also found in: Dictionary, Thesaurus, Acronyms, Idioms, Encyclopedia, Wikipedia.
a rodent with a very short tail that is not visible externally; native to South America, where it is raised for food; used widely as a laboratory animal in medical research.
Synonym(s): guinea pig
1. Any of various small, stocky, short-eared rodents of the genus Cavia of South America, having no visible tail. The domesticated species C. porcellus is widely kept as a pet and is used in biomedical research.
2. Informal A person who is used as a subject for experimentation or research.
Vox populi A person used in any empirical situation, analogous to guinea pigs, which in fact have very limited usefulness as experimental animals; although use of the analogy has continued, the use of guinea pigs as test animals has not.