Relative clauses attach extra information to a noun, and they come in two types: defining and non-defining. Defining relative clauses are essential to the meaning of the sentence—they specify which person or thing we're talking about. Without them, the sentence would lose important information. Non-defining relative clauses, on the other hand, add extra information that isn't necessary to identify the noun. They are set off by commas, and if you remove them, the main sentence still makes complete sense.
- Defining relative clauses are essential to the meaning of the sentence.
- Non-defining relative clauses add extra information and are set off by commas.
- Removing a non-defining relative clause does not change the main meaning of the sentence.
Defining clauses provide essential information; non-defining clauses add extra information.
Source Material
Author: Grammarly
Document: Defining and Non-defining Relative Clauses
Date Published: 2024
Defining Relative Clauses
Defining relative clauses specify exactly which person or thing we are talking about, making the meaning of the sentence clear and precise. They are not separated by commas because the information they provide is essential. The relative pronouns used in defining clauses are typically who (for people - subject), whom (for people - object), which (for things/animals), and that (for people or things in informal contexts).
- Provide essential information that defines the noun.
- No commas are used.
- Relative pronouns: who, whom, which, that.
- If removed, the sentence loses critical information.
Example:
The book that you lent me is fascinating.
(The clause "that you lent me" tells us exactly which book, so it's defining.)
The car that he drives is new.
Yes, for people or things.
Non-defining Relative Clauses
Non-defining relative clauses add extra, non-essential information about a noun that is already clearly identified. They are always set off by commas, and if you remove the non-defining clause, the main sentence still makes sense. The relative pronouns used in non-defining clauses are usually who (for people) and which (for things). Note that "that" is NOT used in non-defining clauses.
- Add extra, non-essential information.
- Always use commas to separate the clause.
- Relative pronouns: who, which (not that).
- If removed, the main sentence still makes sense.
Example:
My brother, who lives in New York, is coming to visit.
(The clause "who lives in New York" just adds information; you still know who "my brother" is.)
'that' cannot be used in non-defining relative clauses.
Yes, they are set off by commas.
My father, who is a doctor, works at the hospital.
Summary
| Feature | Defining Relative Clauses | Non-defining Relative Clauses |
|---|---|---|
| Purpose | Essential info to identify the noun | Extra, non-essential info |
| Use of Commas | No | Yes |
| Relative Pronouns | who, whom, which, that | who, which |
| Can You Remove the Clause? | No (changes meaning) | Yes (main meaning remains) |
| Example | The girl who sings is my friend. | My sister, who sings, is very talented. |
Defining clauses use who, whom, which, and 'that'.
Commas are used, and 'who' and 'which' are typical pronouns for non-defining clauses.
Source Material
Author: EF English Live
Document: Relative Clauses: Defining and Non-defining
Date Published: 2024
Understanding the difference between defining and non-defining relative clauses helps you use relative pronouns correctly and structure sentences with the right nuance.
- Defining clauses give essential info—no commas, and you can use "that."
- Non-defining clauses add extra info—use commas, and don't use "that."
- Mastery of these clauses improves both clarity and style in writing and speech.