What is a Non-Defining Relative Clause?

A kind of relative clause, a non-defining relative clause, tells us about the subject of a sentence, but the knowledge doesn’t help to define what we’re talking about.

The information included in the clause is extra: it’s not essential for understanding the sentence. For this reason, a non-defining relative clause might also be called a non-essential relative clause.

Take a look at this example:

  • The garden, which was full of blossoming flowers, overlooked the hill.

In this sentence, the clause ‘which was full of blossoming flowers’ is a non-defining relative clause. It’s not essential for understanding the rest of the sentence, but it helps to paint a clearer picture. It doesn’t define the garden either – it just gives us something extra. If we removed the non-defining relative clause from the sentence, like so:

  • The garden overlooked the hill.

It still makes complete grammatical sense.

How do you write a Non-Defining Relative Clause?

Non-defining relative clauses contain a few main things: a relative pronoun, a verb, and other optional elements, such as the verb’s subject. It would help if you used commas, hyphens, or brackets to split the non-defining relative clause from the rest of the sentence.

The clause most commonly appears in the middle or end of a sentence.

Which relative pronouns can you use in a Non-Defining Relative Clause?

It would be best if you used the following pronouns: who, whose, whom, which, and where.

How is a Non-Defining Clause different from a Defining Relative Clause?

As we’ve already established, the information in a non-defining relative clause is non-essential. So, that means the information in a defining relative clause is essential. Here are some other key differences between the two:

  • In a defining relative clause, the relative pronouns who, whom, and which are often replaced with ‘that’ in spoken English. You can’t do this with a non-defining relative clause.
  • In a non-defining relative clause, the pronoun must always be included. However, it can sometimes be removed from a defining relative clause.
  • Defining relative clauses use no punctuation, whereas non-defining ones need to be separated from the other clause(s) using commas, hyphens, or brackets.

Here is an example to compare.

Non-defining Defining Explanation
She gave me a cupcake, which was red velvet flavored. She gave me a cupcake that was red velvet flavored. The first example gives extra information about a single cupcake. The relative pronoun ‘which’ is used, as well as a comma.

The second example specifies which cupcake was given – implying that there are multiple cupcakes. The relative pronoun ‘that’ is used, and there’s no punctuation with the relative clause.

Non-Defining Clause Introductory Expressions

Sometimes, a non-defining relative clause can be introduced by an expression followed by a relative pronoun (whom or which). These are some of the phrases that you can use:

  • all of;
  • any of;
  • some of;
  • a few of them;
  • much of;
  • each of;
  • both of;
  • either of;
  • half of;
  • many of;
  • much of;
  • one of;
  • two of;
  • none of.

Here’s how you can use them in a sentence:

  • I collect stamps, many of which are vintage.
  • I have lots of cousins, some of whom live abroad.
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