10 Things You Should Know About Plurals


When you want to refer to more than one of a particular noun, you add an s and BINGO, you have a plural noun. Easy, peezy. Right? Of course not! English is one of the most irregular languages; every so-called rule of grammar, spelling, or pronunciation seems destined to be broken.

In the English language, there are lots of ways to get it wrong, so here’s a refresher on 10 things you should know about plurals. And pay attention because the rules here are iffy.

1) Sometimes an "s" is all you need

Typically, to make a plural noun from a singular noun, add an s. This rule, like many English language rules, depends on what sounds good. Many nouns end with sounds that are conducive to just adding an s.

  • dog/dogs
  • banana/bananas
  • airplane/airplanes
  • monkey/monkeys
English is one of the most irregular languages; every so-called rule of grammar, spelling, or pronunciation seems destined to be broken.

2) Sometimes you need an "e" to go with that "s"

Since it has to sound good, nouns that already end with an s-like sound need an es to become plural. Words that end with x, z, sh, s, or a soft ch sound will typically use an es ending in the plural form.

  • box/boxes
  • lunch/lunches
  • boss/bosses
  • wish/wishes

3) Unless the word ends in "f"

If you have a word that ends in f or an f-sound (like safe, which actually ends in e but sounds like f), it might take a simple s to form the plural, or you might need to changes the f  to a v.

  • safe/safes
  • roof/roofs (even though we pronounce it like rooves)
  • loaf/loaves
  • knife/knives

Sometimes the spelling is different in other English speaking regions. According to the Chicago Manual of Style, 15th Ed (CMOS 15), in the U.S. we use wharf/wharves, whereas the Brits uses wharf/wharfs.  The rules here are practically nonexistent. For these, I recommend memorization and a bookmarked link to an online dictionary.

4) And if it ends with an "o"

..that’s a whole other issue. According to CMOS 15, “there is no firm rule for determining” when to use s or es to form a plural from a word that ends in o, but there are two tricks that may help you decide which one to guess.

  • Words that are often used as plurals typically carry the es ending: hero/heroes, potato/potatoes
  • Words that appear to be borrowed from another language, that are proper names, or that are the shortened version of a longer word typically just have an s: bravado/bravados, Leno/Lenos, moto/motos

An exception to this hardly-useful-in-the-first-place rule is the word zeros. No explanation as to why.

5) Nouns that end in “y”

Speaking of y, nouns that end in this letter are often changed to ies when forming the plural version.

  • baby/babies
  • sky/skies
  • pony/ponies

According to CMOS 15, nouns that end in a consonant, or a consonant sound like qu, end with ies in the plural form. However, if the noun has a vowel before the y or if it is a proper noun, then just add an s and go about your day.

  • Betty/Bettys
  • toy/toys

6) Acronyms

If you are still using an apostrophe to indicate a plural form of an acronym, you can be forgiven. This rule has stuck around in the various style guides for quite some time. But like DVDs (not DVD’s as the copywriters of yore would have it), this rule is on its way to becoming completely extinct. To make an acronym into a plural, add a lower case s to the end. That’s all.

  • CEO/CEOs
  • MP3/MP3s
  • VP/VPs

7) Compound nouns

This might be the hardest one to remember. Modern English speakers get it wrong all the time in every day conversation, so it’s hard to remember. Here we go: when two or more words are used together to create a noun, with or without a hyphen, you need to be sure to pick the noun or the main noun (if there is more than one) that is being turned into a plural. The main noun is not always first, nor always last, nor always easy to identify. Let’s parse through a few examples.

  • mother-in-law/mothers-in-law - multiple mothers not multiple laws
  • bus stop/bus stops – multiple stops not multiple busses
  • passerby/passersby – multiple passers not multiple bys (whatever that is anyway.. it’s not a word.)
  • bucketsful/bucketfuls – Ok. Actually, in olden days, they probably would have said bucketsful. And, according to the rules, that would make better sense. Either version works. Just be consistent.

As with all these pesky plurals, it’s best to look it up in a reputable source.

8) Plurals that are the same as their singular form

Some words are interchangeable as either plural or singular. For these words, the reader must look at the context and the verb forms that surround the noun in order to determine whether or not it is being used as a singular noun or as a plural noun.

  • A deer keeps eating my garden./A herd of deer are crossing the road in front of my car.
  • I only caught one fish./My sister caught eight fish!
  • A single sheep grazes in my field./Hundreds of sheep are herded through the mountains each year.
  • Every year, scientists discover a new water-dwelling species./There are multiple species of wasps, and I am afraid of all of them.

9) Latin Words

Modern English is a conglomeration of words from other language origins. German, French, Greek, and Latin words form a significant part of our everyday communication—and we habitually use them incorrectly. Latin words, however, seem to give us the most trouble when it comes to using their singular and plural forms correctly. Last month, a reader of my 10 Words You Literally Didn’t Know You Were Getting Wrong wrote in the comments that it irked her when people used the word forum incorrectly. Forum is the singular noun derived from the Latin word for “a public market.” According to the typical rules for making this into a plural, more than one forum would be fora.  Instead, you have probably heard the word forums used more often.

While it is technically not correct, it sounds fine to our English speaking ears, and as we learned in item one, what sounds good occasionally wins. Language is always evolving, and the rules do change based on common usage. I would not say that forums is wrong if I were to come across it.

Here are a few other Latin-derived words with confusing plurals.

  • Datum/data: Data is a plural noun. Datum is the singular form. I am guilty of using the word data as a singular noun to refer to a group of information pieces that together form a single entity. In English, this concept is called a mass noun. Other examples of mass nouns include herd and furniture. While used as singular nouns in regular use, they refer to a group of items.
    • A herd is a group of animals, typically grazing animals like cows, deer, or antelope.
    • Furniture can refer to a group of items such as chairs, sofas, tables, etc. It can also apply to a single item.

Generally speaking, data is accepted in the English language as a singular or plural. Use datum if you must, but I wouldn’t sweat it. Again, what sounds good usually prevails, and “The data reveal a slight lead” just doesn’t sound right.

  • agendum/agenda: A similar debate exists here. Agenda/agendas has become the normal way that modern English speaker use this word.  You can fight it if you want, but the tides are turning.
  • Medium/media: Each of these words have begun to take on their own meaning. Media typically refers to our news outlets, while medium can mean anything from a material used to create a piece of art to a person who speaks for the dead. I hear media used as a mass noun all the time. I think unless you are specifically using this word to refer to multiple materials used to create something—e.g. a mixed-media art installation—modern bad habits will also win here. Sorry.

Don’t despair, though, purists. There are still plenty of Latin-derived words that have maintained their plural forms.

  • Criterion/criteria
  • Fungus/fungi

10) And then some are just irregular

And then there are those nouns that are just irregular. There are some patterns to observe; here are a few.

  • ou­ to i: mouse/mice, louse/lice
  • oo to ee: goose/geese, foot/feet
  • i to e: basis/bases, crisis/crises
  • x to ces: appendix/appendices, matrix/matrices

And some plurals just don’t make sense. Here are a few to memorize.

  • Person/people
  • Child/children
  • Man/men

When in Doubt

Consult the dictionary. When it comes to plurals, all the rules are meant to be broken. Sometimes a plural word isn’t even a form of the singular, so look it up in a dictionary to be sure.

 Weigh In

What plurals catch you up? Which ones seem surprising? What do you think about the shift away from strict observance of the proper Latin plurals? Inevitable? Sacrilege?

For More Lessons From Taylor, Check Out Her New Class:
Grammar & Style: 2 Weeks To Nail The Basics

Taylor Houston

Column by Taylor Houston

Taylor Houston is a genuine Word Nerd living in Portland, OR where she works as a technical writer and volunteers on the marketing committee for Wordstock, a local organization dedicated to writing education. She has a BA in Creative Writing and Spanish from Hamilton College and attended Penn State's MFA program in Creative Nonfiction. She has taught writing at all levels from middle school to college to adult, and she is the creator of Writer’s Cramp, a class for adults who just want to write!

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Julio Rivera's picture
Julio Rivera November 14, 2012 - 10:35am

The latin plurals really trip people up. Alumnus, Alumna, Alumnae, and Alumni. When sex is brought up in regards to plurals, it further muddles things up.

SumatraBean's picture
SumatraBean from Virginia November 14, 2012 - 7:34pm

When sex is brought up in regards to anything, it muddles things up.

Just sayin'.

p.j.'s picture
p.j. from Amsterdam, Netherlands is reading The Souix March 8, 2013 - 8:05am

i like the idea that the language is evolving. why keep using a form if it sounds awkward? 

from iPhone

Quietist's picture
Quietist April 20, 2018 - 2:05pm

"Aquariums" is a peeve of mine.  "Aquaria" sounds SO much nicer to the ear. ;-)