Main Difference – Defining vs Non defining Relative Clauses
A relative clause is a clause that is introduced by a relative pronoun. Relative clauses act as adjectives since they identify and modify the noun preceding them. They can be grouped into two categories known as defining clauses and non-defining clauses. A defining relative clause is a clause that adds essential information to the main clause. A non-defining relative clause is a clause that adds extra information to the main clause. This is the main difference between defining and non-defining relative clauses.
What is a Defining Relative Clause
Defining relative clauses are clauses that give essential information about the noun they describe. These are also known as restrictive relative clauses or identifying relative clauses. These clauses provide information that is needed to identify the noun; they help us to understand what or who is being referred to by the noun.
This is the lady who won the lottery.
In this example, the relative clause “who won the lottery” helps us to identify the noun “lady”. Therefore, this relative clause adds essential information to the sentence; without this clause, the meaning of the sentence would be incomplete.
Given below are some more examples of defining relative clauses. The relative clause is italicized and the person or thing referred to by the clause is underlined.
You should give this money to somebody who needs it.
I’m playing the role of a woman whose husband was killed in the war.
Can I have the book that I gave you yesterday?
The students who study hard will pass the exam.
Your dog has eaten the cake which I baked this morning.
What is a Non defining Relative Clause
Non-defining relative clauses are opposite of defining relative clauses. These are also known as non-identifying relative clauses or non-restrictive relative clauses. Although these clauses give information on something, they do not define or identify. Non-defining relative clauses add extra or additional information to a sentence. If we were to remove the relative clause from the sentence, the meaning of the sentence would remain the same although there would be less detail.
This emerald necklace, which was given to me by mother, is very expensive.
→ This emerald necklace is very expensive.
As seen from the above example, a non-defining relative clause only adds additional information to a sentence. You might have also noticed that the relative clause in the above example is set off by commas. Commas should be always used at the beginning and the end of non-defining relative clauses. It is also important to notice that the relative pronoun that cannot be used in a non-defining relative clause.
My sister, who is a very good cook, is planning to open a restaurant.
My car, which was parked in the garage, has been stolen.
The heavy rains, which are unusual for this time of the year, caused floods.
Difference Between Defining and Non defining Relative Clauses
Defining relative clauses are clauses that give essential information about the noun they describe.
Non defining relative clauses are clauses that add extra information to the sentence.
Type of Information
Defining relative clauses add essential information.
Non defining relative clauses add additional information.
Defining relative clauses are not set off by commas.
Non defining relative clauses are set off by commas.
Relative Pronoun That
Defining relative clauses can begin with that.
Non defining relative clauses do not begin with that.