guinea_pig
1. [ noun ] a person who is subjected to experimental or other observational procedures; someone who is an object of investigation
Synonyms: subject case
Examples:

"the subjects for this investigation were selected randomly" "the cases that we studied were drawn from two different communities"

Related terms: person
2. [ noun ] (zoology) stout-bodied nearly tailless domesticated cavy; often kept as a pet and widely used in research
Synonyms: Cavia_cobaya
Related terms: cavy