What is a Non-defining Relative Clause?
A non-defining relative clause (also called a non-restrictive relative clause) adds extra information about a noun that is already clearly identified. The information is interesting but not essential to the meaning of the sentence.
Important: Non-defining clauses are ALWAYS separated by commas.
- My brother, who lives in London, is a doctor. (I have only one brother — the clause adds extra info.)
- Paris, which is the capital of France, is beautiful. (Paris is already identified — the clause adds detail.)
- The Eiffel Tower, which was built in 1889, is a famous landmark.
Key Differences from Defining Clauses
| Feature | Defining Clause | Non-defining Clause |
|---|---|---|
| Information | Essential to identify the noun | Extra, non-essential information |
| Commas | No commas | Always use commas |
| Pronoun "that" | Can use "that" | Cannot use "that" |
| Omitting pronoun | Can omit object pronouns | Cannot omit the pronoun |
Relative Pronouns in Non-defining Clauses
Only who (for people), which (for things), whose (for possession), where (for places), and when (for times) are used. "That" is never used in non-defining clauses.
- My grandmother, who is 90 years old, still swims every day. (Person)
- This laptop, which I bought last year, is already outdated. (Thing)
- John, whose father is a famous actor, wants to be a singer. (Possession)
- London, where I was born, is a diverse city. (Place)
- Christmas, when families gather together, is my favourite holiday. (Time)
Important: The pronoun can never be omitted in a non-defining clause.
- My car, which I bought last month, is already in the shop. (Cannot omit "which")
- My boss, who is very generous, gave us a bonus. (Cannot omit "who")
Examples Comparing Defining vs. Non-defining
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Defining: The students who passed the exam celebrated. (Only the students who passed — essential info.)
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Non-defining: The students, who passed the exam, celebrated. (All students passed — extra info.)
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Defining: The car that is parked outside is mine. (Which car? The one parked outside.)
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Non-defining: My car, which is parked outside, is a Toyota. (My car is already identified.)