Relative clauses

Relative clauses (also known as adjective clauses) are a type of subordinate (or dependent) clause used to describe a noun in a main clause. We use them to specify which particular noun we are referring to or to provide additional information about the noun. They are usually introduced using a relative pronoun (that, which, who, whom, whose) and are placed directly after the noun they describe or add information to.

This guide and a number of relative clause activities are available to download as PDF documents.

We can categorise relative clauses in two ways:

• Defining or non-defining relative clauses
• Subject or object relative clauses

Learning the difference between these types of relative clause is important to be able to use them correctly. In the infographic below, you can see a summary of what relative clauses are, how they are structured, and the grammar rules that go with them. Following that, you’ll find a more detailed description.

See also:

Possessive relative clauses with ‘whose’
Relative clauses with relative adverbs
Relative clauses with prepositions
Sentential relative clauses
Reduced relative clauses

Use the link at the bottom of the page to download this infographic as a PDF document

Relative pronouns

In English, there are five relative pronouns – that, which, who, whom and whose – that we use to introduce relative clauses. The relative pronoun replaces the noun being described in the main clause. The table below explains when to use each relative pronoun:

Use the link at the bottom of the page to download this infographic as a PDF document

Defining and non-defining relative clauses

When the relative clause is necessary to identify which specific noun is being referred to, we call this a defining relative clause (also known as an essential or restrictive relative clause).

When the relative clause is not necessary to identify which specific noun is being referred to, we call this a non-defining relative clause (also known as a nonessential or non-restrictive relative clause).

Defining (essential/restrictive) relative clause examples

Consider the following sentence which contains an unspecified noun:

• The bus has been cancelled.

In this sentence, it is not obvious which specific bus has been cancelled, so we need to add a defining relative clause so the other person knows which bus we’re talking about:

• The bus that goes to Manchester has been cancelled.

Here is another example:

• I already broke the phone.

In the sentence above, it is not clear which specific phone has been broken, so we need to use a defining relative clause so the other person knows which phone we are talking about:

• I already broke the phone that I bought last week.

You can see in the examples above that we do not use commas to separate a defining relative clause from the main clause.

Non-defining (nonessential/non-restrictive) relative clause examples

Consider the following sentences, which both contain information about Leonardo da Vinci:

• Leonardo Da Vinci painted the Mona Lisa. Leonardo Da Vinci was an Italian artist.

The noun “Leonardo da Vinci” is already defined, so we don’t need a defining relative clause here. However, we can use a non-defining relative clause to present the two pieces of information in a more concise way to avoid repetition:

• Leonardo Da Vinci, who was an Italian artist, painted the Mona Lisa.

Here is another example. These two sentences both contain information about Paris:

• We visited Paris. We had never visited Paris before.

Again, “Paris” is already defined, but we can use a non-defining relative clause to make these pieces of information more concise and avoid repetition:

• We visited Paris, which we had never visited before.

You can see in the examples above that we separate a non-defining relative clause from the main clause using commas.

Subject and object relative clauses

If the relative pronoun acts as the subject of the verb in the relative clause, this is called a subject relative clause.

If the relative pronoun acts as the object of the verb in the relative clause, this is called an object relative clause (although the relative pronoun still appears at the beginning of the clause).

For example, in the following sentence, you can see that the relative pronoun “that” is the subject of the verb “goes”:

• The bus that goes to Manchester has been cancelled. (The bus goes to Manchester.)

In the following sentence, “you” is the subject of the verb “met”, and therefore, the relative pronoun “whom” is the object of that verb:

• My brother, whom you met last week, has got a new job. (You met my brother last week.)

Who vs whom

In formal English, we use who as the subject and whom as the object (either of a verb or preposition). However, despite what grammar puritans might tell you, in everyday modern English, most native speakers will just use who as both the subject and object of a verb (although it is still common to use whom as the object of a preposition when it appears directly after the preposition).

Common mistakes with relative clauses

Remember that the relative pronoun acts as the subject or object of the verb in the relative clause, and it is therefore a mistake to add an additional subject or object. This is a common mistake students make when they don’t realise there is already a subject or object. For example:

• The bus that it goes to Manchester has been cancelled. (“that” = the subject, so there is no need for “it”)
• My brother, whom you met him last week, has got a new job. (“whom” = the object, so there is no need for “him”)

When you can omit the relative pronoun

If the relative clause is a defining object relative clause, you can omit the relative pronoun. For example:

• The book (that) I borrowed from the library is due next week.
• The recipe (that) you sent me turned out to be delicious.
• The person (whom) I met at the conference gave an insightful presentation.
• The movie (that) we watched last night was thrilling.
• The guitar (that) my friend plays belongs to his grandfather.
• The teacher (whom) the students admired was awarded for her dedication.

Grammar rules for relative clauses

• Place the relative clause directly after the noun it describes or adds information to.
• Use commas to separate a non-defining relative clause.
• Do not separate defining relative clauses with commas.
• You cannot use that in a non-defining relative clause.
• Which is not usually used in defining clauses (although this is not a strict rule, especially in spoken English).
• In a defining object relative clause, the relative pronoun can be dropped:
  • I already broke the phone (that) I bought last week.
  • He loves the chocolates (that) you bought.
• In a non-defining object relative clause, or in subject relative clauses, the relative pronoun cannot be dropped.
• Avoid double subjects in subject relative clauses.
• Avoid double objects in object relative clauses.

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