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Are you ever unsure how to form plurals? Do you sometimes think an apostrophe is the solution? Then keep reading for easy tips on forming plurals in potentially confusing situations.

If you only remember one thing from this Grammar Corner entry, let it be this:

Apostrophes are almost never used to form plurals.

In the rare case when you want to talk about more than one lowercase letter (a's, b's, c's), you should use an apostrophe to form the plural to avoid confusion. There may be a few other extremely rare cases like this where you need to use an apostrophe to pluralize a word. In all other cases, keep that apostrophe out of your plurals!


Now I'll address some categories of words that often confuse people when it comes to pluralization: 

Irregular plurals

Most plurals are formed by simply adding "s" or "es" to the end of the singular word. For example, "cat" becomes "cats" and "box" becomes "boxes." But some English words take irregular forms when pluralized. Here are some examples:

  • "leaf" becomes "leaves"

  • "child" becomes "children"

  • "woman" becomes "women"

When it comes to irregular plurals, remember that the dictionary is your friend. The plural form will be written out right there in the word's dictionary entry. So if you suspect a word might be irregular and you aren't sure how to pluralize it, look it up! It will only take a second to find your answer.

Words ending in "y"

I often see people incorrectly use apostrophes to form plurals when words end in "y." There's a special rule for this grammatical situation, but I promise you, no apostrophes are involved. Here's the rule:

  • If a vowel precedes the final "y," just add "s" (e.g., days, monkeys, boys)

  • If a consonant precedes the final "y," change the "y" to an "i" and add "es" (e.g., babies, cherries, memories)

Days of the week

If you use social media, you've probably seen at least one post like this: I hate Monday's!

Now that you've been reading this Grammar Corner entry, are you starting to suspect something is amiss with that sentence? If you are, you're right! 

Days of the week don't require any special treatment to form their plurals. (Read: no apostrophe.) Since all the days of the week end in "day," just refer to the rule above about words ending in "y" to figure out what to do. Since a vowel precedes the final "y," just add "s"! Now you can correctly "hate Mondays," "love Fridays," and everything in between.


The theme of "no apostrophe needed" also applies when you want to pluralize a name.

  • Are there five people named Jennifer in your office? Then you work with a lot of Jennifers.

  • Is your neighbors' last name Goldberg? Then you live next to the Goldbergs.


(But if the Goldbergs invite you to dinner, then you'll be eating at the Goldbergs' house. The house belongs to the Goldbergs, so you need to use an apostrophe to form the possessive.)

Acronyms and initialisms

Both acronyms and initialisms are words formed from the first letters of each word in a compound term. The only difference is that acronyms are pronounced like a word (e.g., NASA), while initialisms are read by pronouncing the name of each letter (e.g., ATM). Either way, there's no need to use an apostrophe to make them plural. Simply add "s." For example:

  • This bank has three ATMs.

  • All DVDs go on sale tomorrow.

  • New PINs will be emailed later today.

Decades, ages, and temperatures

  • Are you writing an essay about the era of disco? Then you must be writing about the 1970s.

  • Is your grandma 84 years old? Well then she's in her 80s.

  • Do you need a scarf today? The forecast says to expect temperatures in the 20s, so you should definitely bundle up. 

That's right. You guessed it. No apostrophe needed. Just add "s"!

Compound nouns

Pluralizing compound nouns can be a little tricky. Whether they're hyphenated or not, focus on pluralizing the main word in the compound noun, not descriptor words. For example:

  • "mother-in-law" becomes "mothers-in-law"

  • "attorney general" becomes "attorneys general"

To sum up, save your apostrophes for contractions and possessives. They're almost never used to form plurals. And if you're ever unsure about how to pluralize a word, don't hesitate to follow one of the golden rules of copyediting: When in doubt, look it up! 

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