|1.||a domesticated cavy, probably descended from Cavia porcellus, commonly kept as a pet and used in scientific experiments|
|2.||a person or thing used for experimentation|
|[C17: origin uncertain: perhaps from old use of the name Guinea to mean any remote unknown land]|
guinea pig guin·ea pig (gĭn'ē)
Any of various small, short-eared domesticated rodents of the genus Cavia, having variously colored hair and no visible tail. They are widely kept as pets and often used as experimental animals.