DEFINING RELATIVE CLAUSE AND NON-DEFINING RELATIVE CLAUSE:

A relative clause contains a relative pronoun.

Before we begin, let’s look at ‘clause’ and ‘relative pronoun’.

A clause is a group of words that has a Subject and a Predicate.

‘Predicate’ is the part of a sentence that makes a statement about the Subject. It contains ‘verb’.

Here’s an example:

The little cat   moved to the corner.

Subject                    Predicate

Now, read the following:

I saw a man. He was blind.

I saw a man who was blind.

In this sentence, the word ‘who’ is a pronoun used in place of a noun. It relates to the noun (the man) that comes before it. So it is called ‘Relative Pronoun’.

Let’s move further. The part ‘who was blind’ has a Subject (who) and a Predicate (was blind). It is a clause and it has Relative pronoun. Hence it is ‘Relative Clause’. This clause relates to the noun, ‘man’.

Now that we have understood what a ‘Relative Clause’ is, we’ll learn ‘Defining and Non-defining Relative Clauses’.

Look at the following example:

A man who has three daughters, says, “My daughter is coming here today.” Can we understand which daughter he is talking about? No. We need something to define or specify ‘My daughter’. Now, look at this:

This time, the man says, “My daughter who lives in Chennai is coming here today.”

The clause ‘who lives in Chennai‘ defines very clearly which daughter he is talking about. It defines the noun ‘My daughter’.

Without that clause, there is no sense. Hence we call it ‘Defining Relative Clause.’

More examples:

The book which you recommended is extraordinary.

The woman who stole the clothes has been arrested.

Look at the following example:

A man who has only one daughter, says, “My daughter is coming here today.”

Since he has only one daughter, we need not define who that daughter is. So, there’s no need to use a Relative Clause to define it.

But if we want to add extra information to the noun, we can use a clause.

As it does not define but just adds information, we call it ‘Non-defining Relative Clause‘. But a non-defining clause must be separated from the main clause with commas (,) or hyphens (-), as,

My daughter, who lives in Chennai, is coming here today.

Here are the definitions of Relative Clause:

A defining relative clause defines or specifies a noun/pronoun and without that, the main clause is incomplete.

A non-defining relative clause does not define a noun/pronoun but adds extra information to it. Without that, the main clause still makes sense.