Defining and Non-Defining Relative Clauses

Introduction to Relative Clauses

Before discussing defining and non-defining relative clauses, it's important to understand what a relative clause is. A relative clause is a type of clause that contains the element in question, also known as the antecedent, along with a relative pronoun or adverb. The relative clause usually comes immediately after the noun it is describing. Relative clauses can either be defining (restrictive) or non-defining (non-restrictive).

Defining Relative Clauses

Defining relative clauses, also referred to as restrictive relative clauses, give essential information about the noun or pronoun it follows. They are necessary for the complete understanding of the sentence. If removed, the meaning of the sentence is altered or becomes unclear. These clauses do not require punctuation to separate them from the rest of the sentence.

Examples of Defining Relative Clauses:

  • The book that you lent me is fascinating.
  • The woman who lives next door is a doctor.
  • Forming Defining Relative Clauses

    Defining relative clauses are introduced by relative pronouns or sometimes by a relative adverb. These include: that, who, whom, whose, which, where, when, and why.


  • The dog that bit me ran away.
  • The man whom you saw yesterday is my father.
  • However, in everyday English, we normally use 'that' instead of 'whom' or 'which'. Also, 'that' and 'whom' can often be omitted when they are the object of the verb.


  • The dog (that) I own is a Labrador.
  • The book (that) you bought is on the table.
  • Non-defining Relative Clauses

    Non-defining relative clauses, also known as non-restrictive relative clauses, provide additional information that is not essential to the understanding of the sentence. This information, if removed, does not alter the main message of the sentence because it is merely additional data. These clauses are usually separated from the rest of the sentence by commas, parentheses, or dashes.

    Examples of Non-defining Relative Clauses:

  • My sister, who is older than me, lives in New York.
  • The Eiffel Tower, which is located in Paris, is a popular tourist destination.
  • Forming Non-Defining Relative Clauses

    Non-defining relative clauses are introduced by relative pronouns (who, which, whose), but never by 'that'. Also, these pronouns cannot be omitted. Moreover, in non-defining relative clauses, we use 'whom' to refer to people when it is the object of the verb.


  • My brother, whom you met at the party, is moving to Germany.
  • Jane, whose parents are Italian, speaks fluent Italian.
  • Additional Rules

    In defining relative clauses, we can use 'where' for place and 'when' for time. However, in non-defining relative clauses, we only use 'which' to refer to a whole situation, or we use 'at which' for a particular time.


  • The park where we used to play has been demolished. (defining)
  • The town where I was born is famous for its architecture. (defining)
  • He failed his driving test yesterday, which wasn’t surprising. (non-defining)
  • There was an earthquake last night, at which point everyone ran out of the buildings. (non-defining)
  • Conclusion

    Understanding the differences between defining and non-defining relative clauses is crucial for creating clear and effective sentences in English. They help provide vital or extra details and paint a more complete picture for the reader or listener. When properly applied, these clauses greatly enhance our writing and speaking skills, making our communication more engaging, informative, and meaningful.

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