What are Non-defining Relative Clauses?
Non-defining (or non-restrictive) relative clauses provide extra information about a noun that is already clearly identified. Unlike defining clauses, this extra information is not essential to the sentence meaning — it is an add-on. These clauses are always enclosed in commas (or dashes) and use who, which, or whose. They are common in formal writing and spoken explanations.
Non-defining relative clauses add extra (optional) information about an already-clear noun, enclosed in commas. They use who, which, or whose; removing the clause does not change the core meaning.
- •Essential info
- •Narrows down which noun
- •Can't be removed
- •No commas
- •Extra/bonus info
- •Noun already identified
- •Can be removed
- •Commas before & after
Step-by-step worked examples
Add extra info in a non-defining clause: 'My sister works here.' (She lives in Paris.)
Noun is clear: 'My sister' (you know who) Add extra: 'My sister, who lives in Paris, works here.' Test: Remove clause — 'My sister works here' still makes sense. Commas required ✓
Non-defining with 'which': 'The conference was informative.' (It lasted three days.)
Clear noun: 'The conference' Add detail: 'The conference, which lasted three days, was informative.' Test: Remove it — 'The conference was informative' is complete. Commas required ✓
Non-defining with 'whose': 'Albert Einstein died in 1955.' (His theories revolutionized physics.)
Clear subject: 'Albert Einstein' Add fact: 'Albert Einstein, whose theories revolutionized physics, died in 1955.' Test: Removing the clause leaves a complete sentence. Commas required ✓
Flashcards
Quick quiz
Q1.Which sentence has a non-defining relative clause?
Q2.Which sentence is correct?
Q3.True or False: You can omit 'which' in this sentence: 'The report, which was urgent, arrived late.'
Q4.Which relative pronoun is NOT used in non-defining clauses?
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Common mistakes
Forgetting commas around a non-defining clause. — Correct: Non-defining clauses must have commas before and after (or dashes).
Using 'that' in a non-defining clause. — Correct: 'that' is only for defining clauses. Use 'who', 'which', or 'whose' for non-defining.
Using 'which' for people in non-defining clauses. — Correct: Use 'who' for people, 'which' for things, even in non-defining clauses.
Omitting the relative pronoun in a non-defining clause. — Correct: Always keep the pronoun; you cannot omit it like in some defining clauses.
FAQ
What is a non-defining relative clause?
A clause that adds extra (optional) information about an already-clear noun, enclosed in commas, using who/which/whose.
What is the difference between defining and non-defining clauses?
Defining: essential info, no commas, identifies the noun. Non-defining: extra info, with commas, noun already clear.
Can you use 'that' in non-defining clauses?
No — 'that' is only used in defining clauses. Non-defining uses only 'who', 'which', or 'whose'.
Can you remove a non-defining clause and keep the meaning?
Yes — the core meaning stays intact. You lose the extra detail, but the sentence is still complete and clear.