The Only Plural Nouns Guide You Need: Tips & Tricks to Master Every Form

In 1992, Dan Quayle was Vice President of the United States. During what should have been an uneventful appearance at an elementary school, something unexpected happened: he misspelled potato.

While younger generations won’t recall the event, this gaffe endured, and the details are easy to find: Quayle’s Wikipedia page includes the subheading “Potatoe” within the chronology of his Vice Presidency, and Quayle himself penned an entire chapter on the subject for his memoirs.

You can trace the Vice President’s mistake (which he has attributed to cue cards provided by the school) back to a mixup between singular and plural nouns. His incorrect potatoe was halfway to the plural noun potatoes.

This guide to plural nouns is here to help you go beyond merely learning to define plural noun, providing guidance on their rules for plural noun formation and define plural noun usage, as well.

Don’t forget: our paper checker can help you catch errors and typos and, with any luck, avoid large-scale public spelling embarrassments. Read on to answer, “What is a plural noun?” and to understand what does plural noun mean. 

What is a Plural Noun?

The definition of plural noun can be summed up as a word used for more than one person, place, thing, or idea. Click to read more about increasing numbers for other parts of speech. When answering, “What is a plural noun?,” you first need to understand this plural noun definition.

When a grammatical error occurs with this part of speech, the mistake is typically in the formation and lack of understanding of what plural noun means. Keep reading to learn the rules and see examples of regular and irregular structures.

Forming Regular Plural Nouns

Once you understand the plural noun definition, you’re ready to learn how to form regular and irregular plural nouns.

What is a regular plural noun example? Those considered regular follow standard rules (for the most part) to change their number.

Nouns Ending in Consonants

For nouns ending in most consonants, add an s. Here are examples of plural nouns with this formation:

• dog = dogs
• books = books

For those ending in s, sh, ch, z, or x, add es. See below for examples of plural nouns with this formation:

• dish = dishes
• box = boxes

Exception: if the ch sounds like a k, add only s: stomachs, lochs.

Nouns Ending in Y

For words ending in y preceded by a consonant, change the y to i and add es. See below for examples of plural nouns with this formation:

• country = countries
• fly = flies

For words ending in y preceded by a vowel, add an s. Here are two examples with this formation. 

• monkey = monkeys
• toy = toys

Nouns Ending in F or Fe

For some words ending in f or fe, add an s. Here are two examples with this formation:

• roof = roofs
• chef = chefs

Other words ending in f or fe change the f to v before adding s or es. Here are two examples with this formation:

• knife = knives
• thief = thieves

Nouns Ending in O

For most words ending in o preceded by a vowel, add an s. Here are a couple of examples with this formation:

• studio = studios
• video = videos

Words ending in o preceded by a consonant usually change their number by adding es. See these two examples of this formation:

• potato = potatoes
• hero = heroes

Some words ending in o preceded by a consonant add only an s:

• sopranos = sopranos
• solo = solos

Finally, some words ending in o preceded by a consonant add either s or es, as both are considered correct. These examples are unique in that you learn their proper usage through language learning, and both are grammatically acceptable:

• mango = mangos/mangoes
• banjo = banjos/banjoes

For guidance on which to use in your academic or professional writing, check with your style guide. Our citation resources can help guide you in APA format and more styles.

Forming Irregular Plural Nouns

A plural noun definition simply means a noun changes in number, but its spelling can change considerably if it is formed irregularly. Now that we understand what is a plural noun, we have to ask: What are irregular plural nouns? Unlike their regular plural noun cousins, irregular plural nouns don’t follow any hard and fast rules in their formation. It’s best to just memorize the irregular plural nouns and their respective formations as part of understanding the definition of plural noun. There are, however, some patterns that they follow, as seen in these examples of irregular plural nouns.

Formation Patterns of Irregular Plural Nouns

Some nouns swap oo for ee, like these:

• goose = geese
• tooth = teeth

Some nouns swap a for e, such as these:

• man = men
• woman = women

Other nouns change considerably and must be learned in their specific usage:

• mouse = mice
• person = people

Exception: When referring to a computer mouse, use mouses, not mice.

Singular and Plural Nouns that Stay the Same

Some singular and plural nouns do not change at all to represent pluralization. With this type of plural noun, whether or not they are singular or plural nouns are determined through the context in which they are used.

• fish
• moose
• buffalo

Fish, for example, refers to one fish in the phrase caught a fish. In the phrase plenty of fish, however, it refers to many fish. Therefore, the term fish is a part of both singular and plural nouns grammatically. To define plural noun usage for both of these terms, pay close attention to the other parts of speech in the sentence, especially the verb.

For more examples of regular and irregular formation, see this.

Forming Plural Possessive Nouns & Examples of Plural Possessive Nouns

In this section, you’ll review examples of plural possessive nouns and learn how to form them, remembering to always ask, “What is a plural noun?” Plural possessive nouns are plural nouns first, possessive nouns second. Plural possessive nouns are modified at the end of plural nouns by adding specific punctuation. They are surprisingly quite common in both conversation and writing. However, the rules are crucial when writing, since that is what can be seen and judged accordingly. 

The rules for forming plural possessive nouns can trip up even the most experienced writers. Luckily, they follow a short set of possible standards that can be quickly learned. If you’re ever unsure, consult with your style guide to define plural noun usage per the guide’s advice. In addition to our citation creator, we also have style guide resources for MLA format, and others, that can help.

For a plural noun that ends in s, add an apostrophe to show possession. Here are a few examples of plural possessive nouns with this formation:

• the dogs’ bones
• the knives’ blades
• the designers’ clothes

For a plural noun that does not end in s, add ‘s to show possession. Here are a few examples of plural possessive nouns with this formation:

• men’s clothing
• children’s room
• people’s beliefs

Forming Compound Plural Nouns

Increasing the number of a compound word is another area that can seem tricky at first but is easy to do once you learn the patterns that these words follow and recall the plural nouns definition as simply being more than one of any given noun.

Compound nouns written as one word change their number by adding s or es:

• spoonfuls
• leftovers
• letterheads

Compound nouns that are separated by spaces or joined by hyphens usually increase their number by adding an s to the primary word.

• runners-up
• poets laureate
• lieutenant governors

The primary word is the word that is modified. Notice in the first example, runners is the noun, while up is playing the role of an adverb. Laureate plays the role of an adjective, along with lieutenant in the last two examples.

If you’re unsure which word is being modified, you can figure it out by temporarily changing the number of all parts. Mother-in-law, for example, is a compound to name one person. To identify the primary word, you need to identify which word is being modified. Using the tip above, you would figure this out by increasing the number for both parts and comparing their meanings.

What does each plural noun mean? Mothers refers to more than one mother, while laws is referring to more than one law. Mothers-in-law, therefore, is the correct formation, indicating more than one mother-in-law.

Some compound words increase their number irregularly:

• drive-ins
• six-year-olds
• has-beens

Words that fall under the third rule are typically those with no apparent primary word. You’ll need to commit these outliers to memory, or else check a dictionary for help.

More Examples of Plural Nouns

Following the guidelines above will help you with the formation of most words in determining what is a plural noun in your own writing. There are also instances that require additional consideration.

Some foreign words are pluralized based on root patterns in their original language. These words help determine what is a plural noun example based on their Greek/Latin roots:

• phenomenon = phenomena
• analysis = analyses
• alumnus = alumni/alumnae

English rules are also commonly applied to foreign words. Here are a few plural noun examples that do not follow the rules of their original language:

• formula = formulas
• thesaurus = thesauruses
• index = indexes

Some foreign words can use both the English and foreign formation, so check your dictionary or style guide to determine which form is appropriate when you’re unsure.

Finally, numbers, letters, signs, and words can sometimes become plural nouns when ‘s is added.

While these may seem out of place, remember: what is a plural noun? An accurate  plural noun definition requires identifying more than one person, place, thing, or idea. The plural noun examples below are in context for clarity:

Words:

• She used three and’s in this sentence.

Numbers:

• There are two 4’s and no 0’s in the answer.

Letters:

• To talk of two Mississippis, you’ll need five s’s and two p’s.

Signs:

• A company logo can cleverly incorporate several +’s in its design.

Published March 4, 2019. Updated June 17, 2020.