Defining clauses, also known as restrictive relative clauses or identifying relative clauses, add essential information to the sentence. It helps to identify a specific person or thing from a larger group. For example,
The students who do not study will fail the exam.
The accident that happened yesterday was the truck driver’s fault.
If you remove a defining relative clause from the sentence, the meaning of the sentence changes significantly. Moreover defining relative clause is not separated from the rest of the sentence by commas.
Non-defining clauses are the opposite of defining clauses. They add additional information to the sentence. Removing a non-defining clause will not change the overall meaning of a sentence. Moreover, they are always set off from the rest of the sentence by commas. For example,
My aunt, who was born in Paris, lived most of her life overseas.
He is always late, which is a really bad habit.
How to Use Where in Relative Clauses?
Where is a relative adverb, not a relative pronoun. However, it is sometimes used at the beginning of a relative clause. We use where in relative clauses to indicate a place.
The corner store, where we usually buy our food, was robbed.
This is the place where Lady Elizabeth was killed by highwaymen.
Baker Street is the street where Sherlock Holmes lived.