guinea pig

noun

1

: a small stout-bodied short-eared tailless domesticated rodent (Cavia porcellus) of South American origin often kept as a pet and widely used in biological research

called also cavy

2

: a subject of research, experimentation, or testing

Examples of guinea pig in a Sentence

He volunteered to act as a guinea pig in the experiment.

Recent Examples on the Web

Phone bans emerge as a rare bipartisan issue While Wakefield is a guinea pig for its district by implementing the pouches, phone-free schools are becoming more common across the country. —Shoshana Dubnow, CNN Money, 2 Apr. 2025

The bill applies to dogs, cats, rabbits and guinea pigs. —Kaitlin McCallum, Hartford Courant, 1 Apr. 2025

After all, the 2024-25 season is the guinea pig year. —Charles Baggarly, Fort Worth Star-Telegram, 3 Mar. 2025

Like with pet hamsters and guinea pigs, rabbit owners could think their animal appears fine one evening, only to find the creature dead in its enclosure the next morning from a stomach rupture or gastrointestinal stasis, Valand said. —Claire Thornton, USA TODAY, 11 Jan. 2025

Word History

First Known Use

1664, in the meaning defined at sense 1

Rhymes for guinea pig

• whirligig
• big
• brig
• brigg
• dig
• fig
• gig
• jig
• mig
• prig
• rig
• sprig

Kids Definition

guinea pig

noun

1

: a small stocky rodent with short ears and a very short tail that is often kept as a pet and is used in biological research

2

: a person or thing experimented on

Medical Definition

guinea pig

noun

guin·​ea pig ˈgin-ē-ˌ 

: a small stout-bodied short-eared nearly tailless domesticated rodent of the genus Cavia (C. cobaya) often kept as a pet and widely used in biological research

called also cavy