Defining Relative Clauses

B1 · IntermediateRelative Clauses

The book that I borrowed was excellent. No commas — the clause tells you exactly which book.

What you'll learn

  • A defining relative clause identifies exactly which person or thing is meant
  • Defining relative clauses are never separated by commas
  • Removing a defining relative clause would lose essential meaning
  • For pronoun choice (who/which/that/whose) and when you can omit the pronoun, see Relative Pronouns

Essential information, no commas

A defining (or restrictive) relative clause tells you exactly which person, thing, or group is being talked about. Without it, the sentence would be too vague — you wouldn't know which one is meant. Because this information is essential, defining relative clauses are never set off with commas.

"The book that I borrowed was excellent."
"The student who scored highest won the prize."

Which one is meant?

Ask yourself: if I removed this clause, would the reader still know exactly who or what I mean? If the answer is no, the clause is defining, and no commas are used.

"The car that hit the fence was towed away."
"The waiter who served us was very friendly."

The no-comma rule

This is the single most important rule for defining relative clauses: never put a comma before or after them. Adding commas would turn the clause into a non-defining one, which changes the meaning to 'extra, non-essential information' — see Non-Defining Relative Clauses for that pattern.

"People who exercise regularly feel better."
"The email that arrived this morning needs a reply."

Real English

"The photo that was taken in Iceland won an award."
"The employee who solved the problem got a bonus."
"The restaurant we visited last night was excellent."
"The laptop that I bought last year still works fine."

Watch out

✗The book, that I borrowed, was excellent.
✓The book that I borrowed was excellent.

A defining relative clause is never set off with commas — it's essential to identifying which book.

✗My sister, who studies medicine, called me. (used when you have several sisters and need to specify which one)
✓My sister who studies medicine called me.

If you need the clause to identify WHICH sister, drop the commas — commas signal extra, non-essential information instead.

✗The restaurant, we visited last night, was excellent.
✓The restaurant we visited last night was excellent.

Even when the relative pronoun is omitted, a defining relative clause still takes no commas.

Real life — Describing something specific

"Which jacket do you mean?"

"The one that has a hood — the jacket that I left on the chair."

"Oh, the jacket that Sam borrowed last week?"

"Yes, that's the one that I need back."

Practice

Exercise 1 · Choose the correctly punctuated sentence

Choose the correctly punctuated sentence.

Exercise 2 · Choose the sentence with an essential clause

Which clause is essential to know WHICH student is meant?

Exercise 3 · Choose the sentence with essential meaning

Choose the sentence where removing the clause would lose essential meaning.

Exercise 4 · Choose the correctly punctuated sentence

Choose the correctly punctuated defining relative clause.

Exercise 5 · Choose the sentence that identifies which one

Which sentence identifies exactly which house is meant?

Exercise 6 · Choose the correctly punctuated sentence

Choose the correctly punctuated sentence.

Exercise 7 · Choose the sentence that narrows down which item

Choose the sentence where the clause narrows down which item is meant.

Exercise 8 · Choose the correctly punctuated sentence

Choose the correctly punctuated sentence.

Exercise 9 · Combine the sentences

Combine into one sentence with a defining relative clause (no commas): 'The photo won an award. It was taken in Iceland.'

Exercise 10 · Combine the sentences

Combine into one sentence with a defining relative clause: 'The employee got a bonus. She solved the problem.'

Exercise 11 · Sort into groups

The dog that barked all night kept us awake.
My neighbor's dog, which barked all night, kept us awake.
The driver who ran the red light was fined.
My uncle, who ran a bakery, retired last year.

0 / 4 sorted

Quick challenge

Five quick questions to check what stuck.

Question 1 / 5

Score: 0/0

Choose the correctly punctuated defining relative clause.

You learned

  • A defining relative clause identifies exactly which person or thing is meant.
  • Defining relative clauses are never separated by commas.
  • Removing the clause would lose essential meaning about which one is meant.
  • For pronoun choice and omission rules, see Relative Pronouns.

Related grammar lessons

IntermediateRelative Clauses

Non-Defining Relative Clauses

Learn how non-defining (non-restrictive) relative clauses add extra, non-essential information — always with commas, and never with 'that'.

IntermediateRelative Clauses

Relative Adverbs: Where, When, and Why

Learn to use where, when, and why as relative adverbs — natural, one-word replacements for 'in/at/on which' and 'for which'.

Upper IntermediateRelative Clauses

Prepositions in Relative Clauses

Learn the two ways to place a preposition in a relative clause: formal (preposition + whom/which up front) and informal (preposition stranded at the end).

Upper IntermediateRelative Clauses

Advanced Relative Clauses

Learn two advanced relative clause patterns: quantifier + relative pronoun (two of whom, most of which) and 'which' referring to a whole preceding clause.

View all lessons in this category