guinea pig

/ˈɡɪni pɪɡ/

//ˈɡɪni pɪɡ// noun

"guinea-pig" is a 9-letter English headword indexed on PlainSpell.

The verdict

“guinea pig” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.

Unranked
below top-frequency English
10
letters

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Any tailless rodent of the genus Cavia, which have short ears and superficially resemble large hamsters.

Key facts for guinea pig
PropertyValue
Headwordguinea pig
LanguageEnglish
Part of speechNoun
IPA/ˈɡɪni pɪɡ/
Letters10
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “guinea pig” sits in English frequency

guinea pig falls outside the top-100,000 ranked English words, the long-tail zone of technical, archaic, or low-frequency vocabulary, exactly where readers second-guess spellings most.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

guinea pig is uncommon English outside the top frequency list, classed as anoun, transcribed /ˈɡɪni pɪɡ/. Rarity is why readers land here mid-draft. 5 senses are on record.

The misspelling generator found no plausible variants for guinea pig, which points to an orthography that plays by predictable English rules. Our confusable-pair dataset has no match for it, since no other headword is close enough in sound or shape to pair with it.

Etymologically, the entry records: The origin of "guinea" in "guinea pig" is uncertain. One theory is that the animals, which are originally from South America, were brought to Europe by way of Guinea, leading people to think they had originated there. "Guinea" was also frequently used in En… The correct English form is guinea pig, spelled G-U-I-N-E-A- -P-I-G.

Definition

  1. 1
    Any tailless rodent of the genus Cavia, which have short ears and superficially resemble large hamsters.
  2. 2
    Any tailless rodent of the genus Cavia, which have short ears and superficially resemble large hamsters.
  3. 3
    A living experimental subject.
  4. 4
    A professional company director, without time or real qualifications for the duties.
  5. 5
    A midshipman in the East India service; (by extension) a low-skilled or non-proficient seaman.

Etymology

The origin of "guinea" in "guinea pig" is uncertain. One theory is that the animals, which are originally from South America, were brought to Europe by way of Guinea, leading people to think they had originated there. "Guinea" was also frequently used in English to refer generally to any far-off, unknown country, and so the name may simply be a colorful reference to the animal's foreignness. Others believe "guinea" may be an alteration of the word coney (“rabbit”); guinea pigs were referred to as "pig coneys" in Edward Topsell's 1607 treatise on quadrupeds. The figurative sense of "experimental subject" was first used in the early 20th century, according to the Oxford English Dictionary, which cites examples from 1913 and 1920. It arose from the once extensive usage of guinea pigs in scientific research since at least the 17th century, which had a peak in popularity in the 19th and 20th centuries, when they were part of groundbreaking germ-theory research and of orbital space flights. Compare Italian cavia, Portuguese cobaia, and the latter's loans into French cobaye, Spanish cobaya, Romanian cobai, and Turkish kobay, all of which mean both "guinea pig" and "volunteer for lab experiment", with the latter often being the commoner sense.

This word in other languages

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "guinea pig"?
"guinea pig" is spelled G-U-I-N-E-A- -P-I-G. The IPA pronunciation is /ˈɡɪni pɪɡ/.
What does "guinea pig" mean?
As a noun, "guinea pig" means: Any tailless rodent of the genus Cavia, which have short ears and superficially resemble large hamsters.
How do you pronounce "guinea pig"?
The IPA (International Phonetic Alphabet) transcription for "guinea pig" is /ˈɡɪni pɪɡ/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "guinea pig"?
The origin of "guinea" in "guinea pig" is uncertain. One theory is that the animals, which are originally from South America, were brought to Europe by way of Guinea, leading people to think they had originated there. "Guinea" was also frequently ... See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “guinea pig”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is G-U-I-N-E-A- -P-I-G - every other letter order is a misspelling in standard orthography.
  • Say it as /ˈɡɪni pɪɡ/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Browse more English words and confusable pairs in the same reference. English words
Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list FrequencyWords open word-frequency list