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11 Irregular Plural Words That Sound Completely Wrong—but Aren’t

We all know irregular plurals like "geese" and "mice." But have you ever heard of "beeves" or "sphinges"? Laugh yourself stupid with our smart grammar quiz.

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The plural of “beef” is…

The plural of beef is… beeves! This is true only for “beef” in the sense of “cow”; If you’re talking about arguments between whiny celebrities on Twitter, then those are beefs. On top of trying to memorize these irregular plurals, you’ve probably been saying these 24 things wrong the whole time.

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The plural of “opus” is…

The plural of opus is… opera! (So, an opera is more than one opus? Mind-blown.) What a crazy irregular plural! Check out these 20 funny grammar jokes word nerds will definitely understand.

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The plural of “sphinx” is…

The plural of sphinx is… sphinges! (Though “sphinxes” is an acceptable secondary option.) These are the grammar myths your teacher lied to you about.

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The plural of “biceps” is…

The irregular plural of biceps is… bicepses! That’s right: “biceps” is a singular word, literally translated from the Latin for “two-headed” (each of your biceps connects to the upper arm via two heads, one short and one long.) Check out how confusing life would be without punctuation.

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The plural of “cul-de-sac” is…

The plural of cul-de-sac is… culs-de-sac. In French, cul-de-sac literally translates to “bottom of a sack.” So, weirdly, the plural culs-de-sac becomes “Bottoms of a sack.” (That sack’s got back!) Brush up of these grammar rules that have changed in the last decade.

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The plural of “nieces and nephews” is…

The plural, gender neutral form of nieces and nephews is… niblings! Yes, it was only coined in 1951—all the more reason to make sure it doesn’t disappear! Always remember these apostrophe rules to idiot-proof your grammar.

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The plural of “attorney general” is…

The irregular plural of attorney general is… attorneys general! Similarly, see also: postmasters general, mothers-in-law, and coups d’etat.

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The plural of “octopus” is…

The plural of octopus is… octopuses! No—NOT octopi. Here’s the deal: “Octopi” is how you would make the word plural in Latin; unfortunately, “octopus” is not a Latin word—it’s Greek. The Greek way to make octopus plural is “Octopodes.” So, why don’t we say that? Because, linguists say, when you add a word to the English lexicon, you give all forms of the word an English inflection. So, octopus becomes octopuses. Silly as it sounds, stick with that. These are the pop culture grammar mistakes that editors hate the most.

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The plural of “lasagna” is…

The plural of lasagna is… lasagne! It refers to the large, flat pasta as well as the dish itself; technically, you should be ordering the lasagne from your favorite Italian bistro. This is the craziest English grammar rule you probably didn’t know.

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The plural of “Prius” is…

The plural of Prius is… Prii! Toyota officially announced this new word after a 2011 vote of more than 1.8 million people. Prii trounced runners-up (another weird plural) including Priuses, Prium, and Prien. Here are 15 words that people say aren’t real—but are.

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The SINGULAR form of “spaghetti” is…

And the singular form of spaghetti is… spaghetto! Similarly (awesomely), the singular form of confetti is confetto, and the singular of graffiti is graffito. Language… it’s greato! Next up, learn the 70 words and phrases you’ve probably been using all wrong.