ˈguinea pig noun [countable]
[Date: 1600-1700; Origin: Guinea, probably by mistake for Guiana, earlier name of Guyana]

1. a small furry animal with short ears and no tail, which is often kept as a pet

2. someone who is used in a scientific test to see how successful or safe a new product, system etc is

[TahlilGaran] Dictionary of Contemporary English ▲

guinea pig
noun
VERB + GUINEA PIG act as Twenty students volunteered to act as guinea pigs.
use sb as
PREP. ~ for Dealers used their clients as guinea pigs for their untried techniques.

[TahlilGaran] Collocations Dictionary ▲

a guinea pig
if someone is used as a guinea pig, new ideas or products are tested on them.
They're looking for volunteers to act as guinea pigs for a new AIDS vaccine.

[TahlilGaran] English Idioms Dictionary ▲