A small round animal with no tail sits in a cage: easy to keep, easy to watch, and so it ends up in classrooms and laboratories alike. Once you picture the cage on the laboratory bench — the creature the new thing is tried on first, before anyone knows how it will turn out — the second use of the word follows on its own.
From the word’s history
Wiktionary calls the origin of 'guinea' uncertain: the animals came from South America but may have reached Europe by way of Guinea; 'Guinea' was also used loosely for any far-off place; and some think it is an alteration of coney, meaning rabbit.
Wiktionary 說 guinea 的來源沒有定論。牠原產南美洲，一說是經由幾內亞一帶被帶進歐洲。也有人認為當時 guinea 只是泛指「很遠、不熟悉的地方」。另有一說是 coney（兔子）變過來的。所以這個名字幫不上理解，記畫面比較實在。
Wiktionary, entry “guinea pig” (kaikki:3f6f69a190036ae4:136397965), etymology note on the uncertain origin of “guinea”.
登入就可以看每一支怎麼連回核心畫面。
原始詞典資料5 筆記錄
以下是外部詞典記錄的用法，摘錄並精簡格式，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
guinea pignoun/ˈɡɪni pɪɡ/
- 1
Any tailless rodent of the genus Cavia, which have short ears and superficially resemble large hamsters.
- 2
Any tailless rodent of the genus Cavia, which have short ears and superficially resemble large hamsters.
- 3
A living experimental subject.
- He became a human guinea pig and was paid by the company.
- [H]e spoke of the unwisdom of volunteering one's services as a guinea pig.
- 4
datedslangA professional company director, without time or real qualifications for the duties.
- 5
obsoletenauticaltransportA midshipman in the East India service; (by extension) a low-skilled or non-proficient seaman.
- A good seaman he is... none of your guinea-pigs.
- I promise you, to me it was no slight penance to be exposed during the whole voyage to the half sneering, satirical looks of the mates and guinea-pigs.
摘錄自 英文維基詞典 English Wiktionary，已精簡格式；依 CC BY-SA 4.0 授權使用，改動後的內容同樣以此授權提供。