Do You Know the 35 Hardest Plurals in the English Language?



Teeth is the plural of tooth. We thought we'd start with something easy.


Syllabi is the plural of syllabus. A syllabus is an outline, usually of a course.


Diagnoses is the plural of diagnosis. Similarly, analyses is the plural of analysis.


People is the plural of person. What rule does this follow?!


Radii is the plural of radius. Well, that's not confusing at all.


Crises is the plural of crisis. For many words that end in "us," change the "us" to an "i" to make it plural.


Indices is the plural of index. Huh? This is just one of those you have to memorize.


The plural of criterion is criteria. We think most people have more trouble with the singular form of this one.


The plural of ox is oxen. Does that mean that the plural of box is "boxen"? Sigh.


The plural of schema is schemata. A schema is a pattern or structure.


The plural of tableau is tableaux. Similarly, the plural of chateau is chateaux.


The plural of die is dice. This is another one where the singular form is more misunderstood than the plural form.


The plural of memo is memos. Hey wait ... aren't we supposed to add an "es" to words ending in "o"?


The plural of mongoose is mongooses. Wait, shouldn't it be mongeese?


The plural of roof is roofs. But if the plural of knife is knives, why isn't the plural of roof "rooves"? We're so confused!


The plural of human is humans. But if the plural of woman is "women," and the plural of man is "men," then why isn't the plural of human "humen"?


The plural of moose is moose. Well, that's not confusing at all.


The plural of potato is potatoes. Similarly, the plural of tomato is tomatoes. But remember, never spell tomato "tomatoe." That's just wrong.


The plural of aquarium is aquaria. We had to double check this one.


The plural of cod is cod. Like deer and hair, cod is the same in both the singular and the plural forms.


The plural of hippopotamus is hippopotami. Similarly, the plural of rhinoceros is rhinoceri.


The plural of hoax is hoaxes. Nope, that's not a hoax.


The plural of axis is axes. Yup, the plural of axis is the same as the plural of axe.


The plural of species is species. In some, very rare, instances, the word "specie" is used as the singular form.


The plural of datum is data. We know what data is, but who knew that the singular form was "datum"?


The plural of millennium is millennia. Add an "l" and you're talking about a generation: millennial.


The plural of census is censuses. No, it's not censai.


The plural of stylus is styli. Sometimes the word "styluses" is used for the plural.


The plural of phenomenon is phenomena. Similarly, the plural of automaton is "automata."


The plural of cello is celli. But why isn't it "celloes"?


The plural of elf is elves. Similarly, the plural of self is "selves."


The plural of scissors is scissors. Similarly, the plural of shorts is shorts.


The plural of cul-de-sac is culs-de-sac. Similarly, the plural of brother-in-law is brothers-in-law.


The plural of passerby is passersby. We think that goes against the rules.


The plural of Kennedy is Kennedys. The rule "change the y to an i and add es" does not apply to proper nouns.

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About This Quiz

Are you a grammar expert? Does the misuse of plurals on the internet drive you nuts? If you think you know more than the average Joe about the plural forms of common, and some uncommon, words, take this quiz to prove your knowledge.

The easiest way to make a word plural is to add an "s." But that doesn't work for every word. Some other rules of plurals include adding an "es" to words that end in "x," "ch," "s,: or an "s-like" sound; add an "ies" and drop the "y" for a word that ends in "y;" and add a "ves" and drop the "f" or the "fe" for words that end in "f" or "fe." But some words don't play by the rules. For instance, if the plural forms of potato and tomato are tomatoes and potatoes, then why isn't the plural of the word memo "memoes" (it's memos)? And some words don't have plural forms at all. For instance, the plural of moose is moose, the plural of fish is fish, and the plural of deer is deer. If you're not confused, then this might just be the quiz for you.

Let's find out how much you really know about irregular plurals.

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