|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]|
|a chattering or flighty, light-headed person.|
|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
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.