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What is a Possessive Noun: The Rules Every College Student Needs to Know

There’s an adage that says possession is nine-tenths of the law. Another, less memorable truth might be this: not knowing how to define possessive noun usage accounts for nine-tenths of grammatical errors.

Okay, maybe not nine-tenths. However, the rules for forming possessive nouns in English are tricky enough to trip up even professional writers. And while an errant apostrophe or extra “s” added to your plural possessive nouns might go unnoticed by nine-tenths of the public, they won’t escape the eyes of your professors.

So what are the rules to define possessive noun use? What is a possessive noun anyway?  How can you tell the difference between possessive nouns and plural nouns? What about when a word is a part of the group of both plural possessive nouns? When do you use an apostrophe or an apostrophe + “s”? These are the questions that turn quick assignments into hours-long sessions of self-doubt. But it doesn’t have to be this way.

Keep reading to learn these rules once and for all, then test your knowledge with our examples of plural possessive nouns, singular possessive nouns and everything in between. If you’re still stuck, our paper checker is always here to help you assuage doubt so you can reclaim your time from the clutches of academic anxiety.

What are Possessive Nouns?

So, you’ve heard of the term possessive in general, and have a basic understanding of its definition. But exactly what is a possessive noun? A possessive noun is a noun that shows possession or belonging. This will generally include an‘s for a singular person possessing one or more persons, places, or things, called a singular possessive noun; and an s’ for more than one person possessing singular or plural persons, places, or things. Here are some examples of plural possessive nouns:

  • Mary’s dog
  • Mary’s dogs

Mary is the possessive noun, and the one dog in the first example belongs to her. In the second example, Mary is still the possessive noun, and now more than one dog belongs to her. Notice the pluralization here lies on the plural noun and not on Mary’s, the possessive noun. Now take a look at these examples:

  • The girls’ jacket 
  • The girls’ jackets

In the above, there are examples of plural possessive nouns. In the first example, there are plural possessive nouns that a single jacket belongs to. In other words, multiple girls own the one jacket. Ever grow up with multiple siblings? The likelihood of several of you sharing the same jacket, even if you’re of different genders, is highly likely! In the second example, however, these siblings are more fortunate. The multiple plural possessive nouns here – the girls – all own their own jackets.

Plural nouns are often confused with possessive nouns, but they are not the same thing. Here are a few plural noun examples:

  • Seven trees
  • Fifty dancing dogs

When you’re unsure if a word is a plural noun, possessive noun, or both, try reversing the words and adding the preposition “of”:

  • Original: Mary’s dog
  • Reversed: Dog of Mary

While you’re unlikely to refer to a dog in this way, doing so would not change your meaning.

  • Fifty dancing dogs
  • Fifty dogs of dancing

With this phrase, you have a new and remarkably unclear meaning. There’s no possession here; these dancing dogs are plural, showing there are more than one, but that they do not define possessive noun use.

Once you can separate possessive noun forms from plural nouns, you’re ready to move on to further define possessive noun use by demonstrating the different kinds of  possessive nouns and their grammatical indicators. If you’re looking to learn about the syntax and semantics of possession, read this entry to get more info.

Singular Possessive Nouns

The apostrophe is a cruel mistress when she’s not given proper care. Allow her some place she doesn’t belong and embarrassment will shortly follow. So where does she belong? Check out this useful link about her myriad uses, and keep reading for her proper use and reinforcement for answering what is a possessive noun when using singular possessive nouns specifically.

In the last section, you learned to answer the question: What is a possessive noun? In this section, you’ll focus more on singular possessive nouns. First, however, you need to sharpen your eye to find words that truly are singular. Here’s a trick you can put into quick use: insert the word one before the word in question:

In the last section, you learned to answer the question: What is a possessive noun? In this section, you’ll focus on singular possessive nouns. First, however, you need to sharpen your eye to find words that truly are singular. Here’s a trick you can put into quick use: insert the word one before the word in question:


  • Adding one to the word girl gives you one girl, which is grammatically correct and confirms that girl is singular.


  • Adding one to the word mice gives you one mice. Even though mice doesn’t end in s, you know it’s the plural form of singular form mouse, as is evidenced by the grammatically incorrect one mice.

Possession Nouns and Apostrophe Rules

After identifying the singular words, demonstrate possession by applying one of these rules. If a word is:

Singular and doesn’t end in s, add ‘s.

  • Mary’s dog
  • The library’s hours

Singular and ends in s, add ‘s (with some exceptions):

  • Agnes’s brother
  • The octopus’s tentacles

Singular and ends in s but pronunciation would suffer from ‘s, add only .

  • Socrates’ writing
  • Moses’ robe

Your ear will help you determine if pronunciation will suffer; the sound made by an s is called a sibilant, and your ear knows how to treat it. For example, in this sentence:

  • Wes’s bicycle was his pride and joy.

The singular Wes shows possession with ‘s. However, it doesn’t work with Socrates instead of Wes:

  • Socrates’s bicycle was his pride and joy.

You can tell it’s wrong because your ear tells you it’s wrong. Try it another way:

  • Socrates’ bicycle was his pride and joy.

This is the correct way to show the relationship between Socrates and his bicycle, and your ear agrees with the words on the page to confirm it. That agreement might even cause you to overlook the other glaring error in that sentence: the bicycle was invented in 1817, over 1,400 years after Socrates’ death.

Any rule with exceptions is a rule worth confirming with your style guide. MLA format, for example, uses ‘s in instances where the AP Stylebook uses only an apostrophe. Our citation services can help you with these and more styles.

Plural Possessive Nouns

There’s an atrocity of the written word tucked away in gardens and hanging proudly on front doors all across America. Examples of plural possessive nouns lovingly painted in elegant script on pallet-wood signs. And they’re all wrong:

  • The Smith’s

The Smiths have omitted a word or abused an apostrophe; they’ve confused plural noun form for the plural possessive nouns . You can avoid this mistake by recalling the rules that define possessive noun use. We learned enough to answer what is a possessive noun in general. What happens when pluralization is necessary and when you need to simultaneously show expression? This is the step that the Smiths skipped.

Possessive nouns have possession of something. The Smiths is plural, representing more than one member of the Smith family. For possessive nouns that are plural and that end in s, an apostrophe after the final s shows possession:

  • The Smiths’ house
  • The dogs’ love of dancing

You’ll notice above that the word house follows the Smiths’. House is the thing to which the Smiths are claiming possession. They might also opt just to drop the apostrophe and the possessive noun’s status with their own name, The Smiths, as their generic plural form, if they don’t need to show ownership of anything.

Not all plural nouns end in s. However, they will appear as possessive nouns like those that are singular, and simply show possession with an ‘s added on to their group. Plurals that end in a letter other than s show possession with an ‘s. Consider these examples of plural possessive noun forms that act like singular nouns in their possessive form:

  • The women’s hammers
  • The People’s Court

Plurals that end in a letter other than s show possession with an ‘s.

Joint Possession and Other Scenarios

In instances of shared possession, the last word in the sequence becomes the possessive noun and demonstrates possession for the previous items in the series.


  • Walter and Jesse’s lab

Walter and Jesse share the lab equally. Jesse, coming last in the sequence of names, is given an ‘s which demonstrates possession for both he and Walter. This is the same as the girls at the beginning of the guide who all share the same jacket due to mom and due’s frugality, and were each named instead of just calling them the generic ‘girls’.

Treat two nouns possessing something different as two separate possessive nouns:


  • Walter’s and Jesse’s arrest warrants.

While Walter and Jesse are both wanted by the police, separate arrest warrants exist. They are each given an ‘s to show possession of their warrants. While this can seem tricky, you can always work through it by answering the question: what are possessive nouns? What is a possessive noun here to achieve in a sentence structure? Starting here will help you identify what you need to show possession of and who or what possesses it. Remember how those multiple girls at the beginning of the guide each owned their own jacket? This is the same pattern followed if each of the girls was named individually.

When one noun possesses another, be sure to show possession based on singular possessive noun forms and plural possessive noun forms and their respective rules.


  • Jonathan’s cousin’s dog 
  • The girls’ mom’s jacket

In the first example, Jonathan has a cousin who has a dog, all of which is in the singular possessive nouns. In the second example, there are multiple girls, who have one mom, and that mom has one jacket. When in doubt, pay attention to the number of people that something belongs to, and the number of people that that person belongs to, and follow the rules of possessive nouns you’ve learned so far.

When multiple people gather and make up a group that is pluralized and modifies another noun, there is generally no need to use possessive forms. Instead, the group is accepted as one single unit. Note that these are exceptions and not the norms. Here are a few examples:

  • Teachers union
  • Workers compensation, or Workers comp

These are usually well known exceptions that are generally commonly known to be written without possessive nouns, and are understood as plural nouns modifying another noun. Practices vary by style guide for this situation.

Very rarely, an apostrophe is used to make a plural form of a noun. When writing about individual letters or numbers, an apostrophe may be appropriate to create the plural form. Note that these are also exceptions and not the norm:


  • Dot your i’s and cross your t’s.

Abbreviations may also be made plural with an apostrophe for certain titles, where appropriate:


  • M.D.’s
  • P.h.D.’s

Of course, your style guide will be the starting point for these choices. Neither the periods nor the apostrophes in the above example would be appropriate in APA format, which instead uses MDs and PhDs. Always refer to your style guide for appropriate modifications.

Possessive Nouns Worksheets

Now it’s your turn to test your knowledge with possessive nouns worksheets. These sample sentences will exemplify how much you understand about possessive forms and the appropriate grammatical feature to indicate that understanding, i.e. apostrophe use.

Test your knowledge with these questions and problems using the information you learned in this guide in these complete the following and show you know the answer to what are possessive nouns. After you’re done, scroll down for the answer key:

  1. What is a possessive noun?
    • A) Any noun that ends in s or es
    • B) Any word that contains an apostrophe
    • C) A noun that shows possession over something

In questions 2-5 in possessive nouns worksheets sentences, choose the correct form for each sentence. Choose either the plural form or the possessive form:

2. The store only sells (mens clothing / men’s clothing).

3. For (heaven’s sake / heavens sake), the Smith family bought another garden sign.

4. The (books pages / book’s pages) were numbered incorrectly.

5. I won’t retweet any of (Molly’s tweets / Mollys tweets) again until she admits to subtweeting me.

For questions 6-10 in  possessive nouns worksheets sentences, modify each sentence so it contains examples of plural possessive nouns or singular possessive noun forms:

6. These feathered hats belong to those ten musicians.

7. The branches of ten trees were damaged by a storm.

8. Mary and Natasha are roommates who have a pet cat.

9. Mary and Natasha are roommates, each with her own pet cat.

10. Socrates hated his sandals because they frequently caught on his robes.


How did you do? Did you ask yourself what are possessive nouns as you worked? Scroll below for the answers.


Answer Key to possessive nouns worksheets sentences

  1. C
  2. men’s clothing
  3. heaven’s sake
  4. book’s pages
  5. Molly’s tweets
  6. These are the ten musicians’ feathered hats.
  7. The ten trees’ branches were damaged by the storm.
  8. Mary and Natasha’s cat is named Louisa May Alcat.
  9. Mary’s cat and Natasha’s cats belong to the two roommates.
  10. Socrates’ sandals were hated by him because they frequently caught on his robes.

Published March 4, 2019. Updated June 15, 2020.

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