Genitive Case Structure and Use in English

Have you ever heard of the genitive case? Your grammar book will tell you that the genitive case, also known as the possessive case, is used when we want a noun to modify another noun. But did you know that we use the genitive case all the time in everyday life?

We use the genitive case to indicate ownership, to describe things, to say where something is from, and even to describe distance or length of time.

In this article, we’ll define genitive case and review the main forms of the genitive case structure. You’ll also learn the many different ways we use the genitive case in daily life.

Genitive case structures

There are three main ways we express a relationship between two nouns in the genitive case. Each structure is used in specific situations, while sometimes they can be used interchangeably.

1) Possessive apostrophe

The first genitive case structure is the apostrophe ‘s’ structure, or the possessive apostrophe:

The man’s truck is parked outside.

The kids’ toys are all over the floor!

In the examples above, the possessive apostrophe of the genitive structure links the two underlined nouns. The first noun is modifying the second noun.

We form this possessive structure by adding apostrophe ‘s’ to the first noun (the modifier). This is the same apostrophe that we use for contractions in English, such as I’m (I am) and we’ve (we have), though the meaning is different.

Depending on the form of the noun, we will add either the apostrophe (‘) and ‘s’ or just the apostrophe.

You can see that when a noun does not end in ‘s’, whether it’s singular or plural, it receives an apostrophe (‘) and an ‘s’ to show possession in the genitive case:

The man’s car is new.

People’s time is valuable to them.

When speaking, make sure to pronounce the ‘s’ clearly. In the following words, it will make a /z/ sound:

man’s– /manz/

people’s – /pee-puhlz/

Nouns that do end in ‘s’ typically get only an apostrophe (‘) added to them:

I don’t like finding the cats’ hair all over the couch!

They offered us some of the chefs’ specialties – they were delicious!

The pronunciation of both words ending in ‘s’ stays the same after adding the apostrophe.

For certain nouns ending in ‘s,’ we may need to add both apostrophe (‘) and ‘s’ if the pronunciation with only the apostrophe sounds awkward. Take a look at the following sentence:

The bus’ schedule is unpredictable.

In this sentence, the pronunciation of bus’ schedule sounds the same as the compound noun bus schedule. The sentence below shows a different way to write it:

The bus’s schedule is unpredictable. (Bus’s is pronounced /bussiz/)

By adding apostrophe (‘) and ‘s,’ we’re able to clearly show the possessive structure through the pronunciation.

Note that the second noun in the apostrophe ‘s’ structure stays the same regardless of the noun that comes before it. Only the ‘possessor’ or modifying noun gets an apostrophe (‘) or an apostrophe ‘s’ added to it.

You won’t find an article (a, an, or the) between the two nouns in the possessive apostrophe structure. There can, however, be adjectives and adverbs between the two nouns if they modify the second noun, as in the example below:

The woman’s youngest daughter was impatient – the girl’s exceptionally well-behaved sister, on the other hand, was incredibly calm.

2) Noun phrases using ‘of’

The second genitive structure used to express a possessive relationship between two nouns is ‘of’ phrases:

Coachella, the musical event of the year in the U.S., takes place every April.

The love of my life proposed to me last night!

The citizens of France are anticipating many delays during the 2024 Olympics.

The ‘of’ phrase structure is formed by placing the preposition ‘of’ between the modified noun and the modifier noun.

Unlike the apostrophe ‘s’ structure, where only the first noun is defined, the ‘of’ phrase structure defines both nouns with an article (a, an, or the), a possessive adjective (such as my or hers) or a determiner (words like this, that, these and those), unless the noun is uncountable or a proper noun. Any necessary modifying adjectives or adverbs are still added.

The table’ s legs are wobbly. → The legs of the table are wobbly.

We won’t be able to complete this tough professor’ s extremely difficult homework!
↓.
We won’t be able to complete the extremely difficult homework of this tough professor!

Later on, we’ll discuss when using the possessive apostrophe is appropriate and when the ‘of’ phrase structure is better.

3) Possessive adjectives and pronouns

In the genitive case, we can also use possessive adjectives and pronouns to express possession.

Take a look at the table below to see the different possessive adjectives and pronouns according to their grammatical person:

Learn more about possessive adjectives with our helpful guide!

Possessive adjectives replace the possessor in the genitive case structure:

The celebrity’s dress was designed by Elie Saab.

Her dress was designed by Elie Saab.

The writer of the U.S. national anthem was Francis Scott Key.

Its writer was Francis Scott Key

Possessive adjectives can also be used within an apostrophe ‘s’ structure or an ‘of’ structure to define one of the two nouns:

My sister’s bedroom is the largest one in the house.

The color of his tie doesn’t match his shirt.

Possessive pronouns can be used on their own to replace the complete genitive case structure. They help us avoid repetition, as you can see in the following examples:

The neighbor’s bike is bigger than mine! (mine = my bike).

The cost of living in your country is higher than ours. (ours = the cost of living in our country).

Genitive case use explained

The genitive case structures above are used to express different noun relationships. Though they can sometimes be used together and interchangeably, each form helps us express specific noun relationships.

The genitive case and possession

One of the main ways we use the genitive case in English is to show a possessive relationship between two nouns. This is why we often call the genitive case the possessive case, though not all genitive case relationships are possessive.

A possessive relationship can be rephrased by using has or belongs to. It tends to reflect a physical possession or a close relationship. To express possession by a person or an animal, we typically use the apostrophe ‘s’ structure or a possessive adjective or pronoun:

The doctor’s office is located on the third floor
(The doctor has an office. The office is located on the third floor.)

The children’s toys are all over the floor!
(The toys belong to the children. The toys are all over the floor.)

Their car is brand new. Ours is not.
(They have a car. The car is brand new. We have a car. The car is not brand new.)

We typically use the ‘of’ phrase structure to show possession by an object. We may also use possessive adjectives:

The wheels of the car are a bit old. They need to be replaced.

The walls of the house need to be repainted. Their color is fading.

The blades of the fan are dusty. We should clean them.

Source and description with the genitive case

Not all genitive case examples show possession. They are also used to describe the source or characteristics of a noun. We can use both ‘of’ phrases or apostrophe ‘s’ in these cases.

Genitive case examples showing source or origin:

The works of Shakespeare have been read by millions over the centuries.

The company’s decision made the shareholders a bit worried.

The president of the country had to cancel his scheduled trip.

Genitive case describing characteristics or quality:

The task’s difficulty made it impossible to complete in a day.

My partner’s ability to listen is one of their best qualities.

Mexican food is distinguished from other foods by the spiciness of its dishes.

The genitive case and measurements

We can also create expressions of measurements with the apostrophe ‘s’ structure in the genitive case. These expressions are often fixed and idiomatic:

A year’s subscription to the magazine is over USD 100.

I live a stone’s throw away from the airport.

Without a moment’s notice, he decided to buy a plane ticket to India.

We rely mostly on the apostrophe ‘s’ structure to form noun relationships in the genitive case. However, ‘of’ phrases are used frequently with fixed expressions or to express complex ideas. It’s also typical to use this second structure when speaking of inanimate objects.

With time and practice, you’ll become familiar with the appropriate way to express origin, characteristics, qualities and measurements through either ‘of’ phrases or the apostrophe ‘s’ structure.

English nouns can be simple or complex. Check out our overview of the types and use of nouns in English.

More genitive case rules

You’ve learned to define genitive case grammar in English, and thanks to the examples of genitive case structures, you can now express noun relationships in multiple ways.

Here are some additional tips to keep in mind about the genitive case.

Mind your spelling

Make sure to follow the spelling rules of the apostrophe ‘s’ structure, especially when dealing with plurals, and don’t confuse the genitive case with contractions of the verbs to be and to have in the third person. The following examples show the difference.

Apostrophe ‘s’: The teacher’s schedule is full. (The teacher’s schedule = The schedule of the teacher)
Toddlers’ nap time is important. (Toddlers’ nap time = the nap time of toddlers)

The verb to be or to have: There’s someone knocking on the door. (There’s = There is)
Carmen’s worked with the company for over 10 years. (Carmen’s = Carmen has)

Possessive adjective its: I forgot to give the dog its food. (its = the dog’s)
If it wasn’t for its unique color, I wouldn’t recognize the house. (its = the house’s)

It’s important to pay attention to these differences in spelling when writing, as they are often confusing for native speakers and English learners alike!

Are you eager to improve your writing in English? Read our tips on practising writing in English.

Leaving out the second noun

Sometimes you can leave out the second noun in the genitive case when using the apostrophe ‘s’ structure if the context is clear:

A: Can I borrow your car?

B: Sorry, I will need it to go to the supermarket. Maybe you can borrow Henry’s.

Henry’s here is understood to mean Henry’s car.

Joint possession in the genitive case structure

As you’ve seen, we can express joint possession by two or more people or by groups using the apostrophe ‘s’ structure with plurals:

The two departments’ decision to implement a hybrid work model was welcomed by all employees.

Our neighbors’ efforts to keep the park clean have been a success.

If we’re expressing joint possession by two separate nouns, we will need to add the apostrophe ‘s’ to the last noun of the group:

Germany and Greece’s decision to leave the diplomatic talks came as a surprise.

In the above example, we understand that it’s a joint decision made by both countries.

Peter and Mary’s Christmas card arrived in the mail last week.

We understand that the Christmas card is from Peter and Mary.

You can express separate ownership by adding apostrophe ‘s’ to each noun in the modifying noun phrase:

David’s and Tom’s laptops were provided by the company.

Apple’s and Microsoft’s stock prices have declined since last year.

In these two examples, we’re indicating that two different people own a laptop (sentence one) and that we’re referring to two companies’ separate stock prices (sentence one). It is therefore not joint ownership, but separate ownership.

The genitive case simplified

We hope this overview of the genitive case has helped simplify the use of apostrophe ‘s’ and ‘of’ phrases in English. While many English learners know that adjectives and adverbs modify nouns and that we can combine nouns to form compound nouns, you’ve now learned that nouns can modify other nouns through the genitive case structure.

The genitive case or the possessive case helps us express relationships between nouns with the use of apostrophe ‘s’ and ‘of’ phrases, as well as with the help of possessive adjectives and pronouns. With the genitive case, we can describe a relationship of possession, a relationship that shows the source of one noun or a description of one noun, and some expressions that describe a measurement.

With so many uses for the genitive case, it’s very useful in everyday conversation and writing. Now that you’ve read all about it, why not take a little time to practice what you’ve learned?