guinea pig

American  

noun

• guinea pigs
  plural

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.

   I've volunteered as a guinea pig in several clinical trials.

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guinea pig British  

noun

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

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Other Word Forms

Noun Inflected Forms

• guinea pigs
  plural

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Etymology

Origin of guinea pig

First recorded in 1655–65

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Example Sentences

See Examples For:

guinea pig

Part of my job is to be a guinea pig, so that I can warn you of the benefits and dangers.

From The Wall Street Journal ● Oct. 4, 2026

At times, this makes the humble viewer feel a bit like a guinea pig in a focus group; the audience’s reactions are integral to measuring the film’s success.

From Salon ● Sep. 19, 2026

"The guinea pig stood on what appeared to be a very thick mat of mud which I believe to be very old, ground down, compacted faeces."

From BBC ● Aug. 14, 2026

"I wouldn't want to be the first guinea pig," as "it's not so easy to have everything just smooth" like Apple has managed to do with its laptops.

From Barron's ● Jun. 1, 2026

Everybody’s health was proposed, from Mr. Laurence, who was considered their special patron, to the astonished guinea pig, who had strayed from its proper sphere in search of its young master.

From "Little Women" by Louisa May Alcott

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Related Words

• experimental subject
• subject
• test subject

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