Meaning & use
non-defining relative clauses
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Meaning
nounpluraltechnical
A clause that adds extra information about a noun but is not needed to identify it.
Grammar: Always plural in this form; the singular is 'a non-defining relative clause'.
Patterns
- a non-defining relative clause
- use a non-defining relative clause
- which introduces a non-defining relative clause
In 'My brother, who lives in Rome, is a doctor,' the words 'who lives in Rome' form a non-defining relative clause.
Non-defining relative clauses are separated from the rest of the sentence by commas.
Teachers often contrast non-defining relative clauses with defining ones, which cannot be left out.
Word forms
| singular | non-defining relative clause |
|---|
Common combinations
- introduce a non-defining relative clause
- You can introduce a non-defining relative clause with 'who', 'which' or 'whose'.
- set off with commas
- Non-defining relative clauses are set off with commas on both sides.
- omit the relative pronoun
- In a non-defining relative clause you cannot omit the relative pronoun.
- defining relative clause
- Unlike a defining relative clause, a non-defining one gives extra, non-essential information.
Synonyms and how they differ
- non-restrictive relative clause
- The more formal term used in linguistics; it means the same thing but appears mainly in academic writing.
- parenthetical clause
- A broader term for any clause added as an aside; it is not limited to relative clauses.
Opposites
Word family
- defining relative clause noun
- A clause that identifies which person or thing is meant and is not separated by commas.
- relative pronoun noun
- A word such as 'who', 'which' or 'that' that begins a relative clause.
Commonly confused: non-defining relative clauses or defining relative clauses?
non-defining relative clauses vs defining relative clauses
Defining clauses tell you which person or thing is meant and take no commas; non-defining clauses only add extra detail and are always marked off by commas.
Practice
Which sentence contains a non-defining relative clause?
Choose one answer.
'My aunt, who called you earlier, is waiting outside' gives extra information about an already identified person and uses commas, which is typical of a non-defining clause. The other options identify which person or thing is meant, so they are defining clauses.
Make it your own
Write a sentence using “non-defining relative clauses”, then check it and compare it with the examples above.