| 1. | a short-eared, tailless rodent of the genus Cavia, usually white, black, and tawny, commonly regarded as the domesticated form of one of the South American wild species of cavy: often used in scientific experiments or kept as a pet. |
| 2. | Informal. the subject of any sort of experiment. |
| guinea pig n.
[Perhaps alteration (influenced by Guinea, used as a name for any faraway unknown country) of Guiana.] |
guinea pig guin·ea pig (gĭn'ē)
n.
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.