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guinea pig

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.
Informal. the subject of any sort of experiment.
Origin of guinea pig
First recorded in 1655-65 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for guinea pig
Contemporary Examples
Historical Examples
  • A guinea pig, a guinea pig, a guinea pig, howled the student of heredity.

  • And they tried to get at Tom—but the guinea pig stood in the way.

    The Book of Dragons Edith Nesbit
  • This guinea pig's name was Jeff, and he and I became good friends.

    Beautiful Joe Marshall Saunders
  • Why has the guinea pig teeth that are shed before it is born?

  • "A guinea pig, like all the others including us," his wife said.

    The Enormous Room Horace Leonard Gold
  • Do you believe there was a guinea pig killed in that cottage?

    The Crime of the Century

    Henry M. Hunt
  • And when he came the Mayor asked him what he called his guinea pig.

    Four Afloat Ralph Henry Barbour
  • He didn't add that he was also a subject, observer and guinea pig in one.

    The Sensitive Man Poul William Anderson
  • To be a guinea pig for some bug they wanted to learn how to kill cheaply and easily?

    The Time Traders Andre Norton
British Dictionary definitions for guinea pig

guinea pig

a domesticated cavy, probably descended from Cavia porcellus, commonly kept as a pet and used in scientific experiments
a person or thing used for experimentation
Word Origin
C17: origin uncertain: perhaps from old use of the name Guinea to mean any remote unknown land
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for guinea pig

1660s, native to South America and perhaps so called either because it was first brought back to Britain aboard Guinea-men, ships that plied the triangle trade between England, Guinea, and South America [Barnhart, Klein]; or from confusion of Guinea (q.v.) with the South American region of Guyana (but OED is against this). In the extended sense of "one subjected to an experiment" it is first recorded 1920, because they were commonly used in vivisection experiments.

Online Etymology Dictionary, © 2010 Douglas Harper
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guinea pig in Medicine

guinea pig guin·ea pig (gĭn'ē)
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.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Slang definitions & phrases for guinea pig

guinea pig


Person or thing used in an experiment, sometimes without agreement: the guinea pigs for her cooking

The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D.
Copyright (C) 2007 by HarperCollins Publishers.
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