Adjective Clause | Examples & Definition

An adjective clause (also called a relative clause) is a group of words with a subject and a verb that is used as an adjective in a sentence to give more information about a noun or pronoun.

Adjective clauses are a type of dependent clause (or subordinate clause), which means they cannot stand on their own as a sentence and must be connected to an independent clause (or main clause).

Adjective clause examples
The pie that Jon brought is very good.

Julie, who is my mom’s best friend, is coming to the wedding.

I am almost finished with this book, which I borrowed from Mauricio.

What is an adjective clause?

A clause is a group of words with a subject and a verb. An adjective clause is used as an adjective in a sentence to modify a noun or pronoun (e.g., “The house that Lily bought is enormous”).

Adjective clauses are a type of dependent clause (a category that also includes adverbial clauses and noun clauses), so they must be connected to an independent clause to form a complete sentence.

Because adjective clauses begin with a relative pronoun (e.g., “who,” “that,” “which”), they are often referred to as relative clauses.

Adjective clauses are often used to combine sentences that refer to the same thing or person. Note that the adjective clause follows the it modifies.

Combining sentences with an adjective clause examples
We are going to Lake Havasu. Lake Havasu is in Arizona.
We are going to Lake Havasu, which is in Arizona.

Give me the keys. The keys are on the table.
Give me the keys that are on the table.

My neighbor is throwing a party. My neighbor is a realtor.
My neighbor, who is a realtor, is throwing a party.

Restrictive vs nonrestrictive clauses

Adjective clauses are categorized as either restrictive or nonrestrictive based on the role they play in a sentence.

Clauses that give essential information about the noun they modify are restrictive clauses (or essential clauses). They cannot be removed from the sentence without changing the meaning or making the sentence unclear. They often answer the question “which one?” Restrictive clauses are not set off by commas.

Restrictive adjective clause examples
The store that is near my house is closing.

Give these flowers to the woman who is standing at the podium.

Nonrestrictive clauses, on the other hand, give nonessential information about the noun they modify. They could be removed from the sentence, and it would still make sense. Nonrestrictive clauses are set off by commas.

Nonrestrictive adjective clause examples
I went to the record store, which is near my house, to buy a gift for Carly.

The president of the university, who is standing at the podium, will give a speech.

Note
In American English, “which” is used only for nonrestrictive clauses.

  •  This is the apartment that I want to rent.
  • This is the apartment which I want to rent.

In British English, “which” can also be used for restrictive clauses.

  •  This is the flat that I want to rent.
  •  This is the flat which I want to rent.

In both dialects, “that” is only used for restrictive clauses.

  • My apartment, that is on the third floor, is very large.
  • My flat, that is on the third floor, is very large.

Relative pronouns

Adjective clauses typically begin with a relative pronoun. The table below describes the most common relative pronouns. These words can have other functions in English, but when used to introduce adjective clauses, they are known as relative pronouns.

Pronoun Function Example
Who Refers to people as the subject of a clause The nurse who was on duty last night was very kind.
Whom Refers to people as the object of a clause The nurse whom I told about my medication is over there.
That Gives essential information about things The ring that Mia is wearing is beautiful.
Which Gives nonessential information about things My ring, which was given to me by my grandmother, is being repaired.
Whose Refers to ownership I told the woman whose dog it is that he is in our yard.
Note
Some sources classify “when” and “where” as relative pronouns in certain contexts, but these words more properly fit in the category of relative adverbs. The words they stand in for (i.e., “then” and “there”) are adverbs rather than nouns.

Omitting the relative pronoun

The relative pronoun can be omitted from a restrictive adjective clause if the pronoun is the object, not the subject, of the clause. This means “that” and “whom” can often be omitted, while “who” and “which” cannot.

Optional pronouns in relative clause examples
I loved the book [that] you recommended.

The man [whom] I gave my ticket to is over there.

Leaving out the relative pronoun is not required, and it is more common in speech than in writing. The one instance where the pronoun is almost always left out is when leaving it in would lead to repeating the word “that.”

Preferred omission of “that” example
  •  The impact that that advertisement had on our business was unexpected.
  • The impact that advertisement had on our business was unexpected.

Adjective clause vs adjective phrase

Both adjective clauses and adjective phrases act as adjectives in a sentence by modifying a noun. Adjective clauses contain a subject and a verb, but adjective phrases do not. As the examples below show, the relative pronoun often acts as the subject of an adjective clause.

Adjective clause vs adjective phrase examples
We have a dog that is exceptionally smart.
We have an exceptionally smart dog.

My friend, who works at a law firm, is meeting me for lunch.
My hilarious and caring friend is coming to visit.

Frequently asked questions about the adjective Clause

What is the difference between restrictive and nonrestrictive clauses?

Both restrictive clauses and nonrestrictive clauses are types of relative clauses (or adjective clauses), which act as adjectives in sentences to describe nouns or pronouns.

  • Restrictive clauses give essential identifying information about the nouns they modify. They often answer the question “which one?” If they are removed from a sentence, the meaning of the sentence is changed or becomes unclear (e.g., “Apples that are picked too early are sour”).
  • Nonrestrictive clauses give extra, nonessential information about the nouns they modify. They can be removed from a sentence without changing its meaning or making it unclear (e.g., “Apples, which are my favorite fruit, are high in fiber”).

Nonrestrictive clauses are set off from the rest of the sentence by commas. Restrictive clauses do not require commas.

What is the difference between an adjective clause and an adverb clause?

Adjective clauses function as adjectives in a sentence to give more information about a noun (e.g., “She wants the kitten that has white paws”). Adjective clauses typically begin with a relative pronoun (e.g., “who,” “that,” “which”).

Adverbial clauses function as adverbs in a sentence to modify a verb, adjective, adverb, or entire clause (e.g., “Let’s go to the movies after we study”). Adverb clauses begin with a subordinating conjunction (e.g., “because,” “until,” “when,” “if”) and frequently answer questions such as “when?” “where?” “why?” or “how?”

Are adjective clauses dependent clauses?

Yes, all adjective clauses (e.g., “that I like the best”) are dependent clauses (that is, they can’t stand on their own as a sentence). There are two other types of dependent clauses: adverbial clauses and noun clauses.

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Kayla Anderson Hewitt, MA

Kayla has a master's degree in teaching English as a second language. She has taught university-level ESL and first-year composition courses. She also has 15 years of experience as an editor.