Nonrestrictive Relative Clause

Glossary of Grammatical and Rhetorical Terms

Couple painting a wall red
The paint, which Mary bought at the hardware store, was bright red.  Frank and Helena / Getty Images

A nonrestrictive relative clause is a relative clause (also called an adjective clause) that adds nonessential information to a sentence. In other words, a nonrestrictive relative clause, also known as a non-defining relative clause, doesn't limit or restrict the noun or noun phrase it modifies.

In contrast to restrictive relative clauses, nonrestrictive relative clauses are usually marked by brief pauses in speech and are usually set off by commas in writing.

Form and Function of Nonrestrictive Relative Clauses

Nonrestrictive relative clauses should be thought of as optional but helpful. Because this is in direct contrast with essential information that appears in restrictive relative clauses, it makes sense that nonrestrictive relative clauses are formatted differently. Authors Kristin Denham and Anne Lobeck illustrate how. "Nonrestrictive relative clauses ... are usually set off by commas in writing, and you can usually detect 'comma intonation' in a speaker's voice, distinguishing the two types.

The paint which Mary bought at the hardware store was bright red.

The paint, which Mary bought at the hardware store, was bright red.

The restrictive relative clause which Mary bought at the hardware store, limits which paint we're referring to, namely to paint which Mary bought at the hardware store. The nonrestrictive relative clause, on the other hand, does not restrict the reference of the noun paint; it is not information that distinguishes the paint from other paint. That Mary bought this paint at the hardware store is simply incidental information," (Denham and Lobeck 2014).

Restrictive vs. Nonrestrictive Clauses

If you're still confused about the difference between a restrictive and nonrestrictive relative clause, perhaps this excerpt from Ammon Shea's Bad English will help: "To make this as short and brutal an explanation as possible, think of a restrictive clause as a liver: a vital organ of the sentence that cannot be removed without killing it. A nonrestrictive clause, however, is more like the appendix or tonsils of a sentence: It may be desirable to have but can be removed without dying (so long as one does so carefully)," (Shea 2014).

Examples of Nonrestrictive Clauses

Here are several more examples of nonrestrictive clauses. To understand how these clauses affect a sentence, try removing each nonrestrictive clause. Because the clauses are nonrestrictive, the sentences from which you remove them should still make sense.

  • Ms. Newmar, who lives next door, claims to be a Martian.
  • For a balloon to float, it must be filled with helium, which is lighter than the air around it.
  • "Besides the bookcase in the living room, which was always called 'the library,' there were the encyclopedia tables and dictionary stand under windows in our dining room," (Welty 1984).
  • "The United States, which presents itself as a global beacon of opportunity and prosperity, is quickly becoming a low-wage nation," (Soni 2013).
  • "Eugene Meyer, who was thirty-two years old, had been in business for himself for only a few years, but had already made several million dollars," (Graham 1997).
  • "Dragonflies kill their prey in the air and eat it on the wing. They feed on aerial plankton, which consists of any sort of small living thing that happens to be aloft—mosquitoes, midges, moths, flies, ballooning spiders," (Preston 2012).
  • "I saw through the front blinds, which my mother always kept at a half-slant—'inviting but discreet'—that Grace Tarking, who lived down the street and went to a private school, was walking with ankle weights strapped to her feet," (Sebold 2002).
  • "A raw new development begins on the other side of my mother's meadow, which she has not been able to mow this fall, since her injuries prevent her from getting up on the tractor,"​ (Updike 1989).

Nonrestrictive Relative Clause Structure and Intonation

Now that you know how to recognize nonrestrictive relative clauses in reading, learn how to use them in your own writing. You'll want to know what structure and intonation patterns to follow to construct clauses that make sense. Start by reading this section from Cognitive English Grammar: "Non-restrictive relative clauses are introduced by the marked relative pronouns who(m) for human referents and which for non-human referents and for situations.

The marked pronoun in conjunction with a caesura [i.e. a pause] before and after the clause clearly sets off the non-restrictive relative clause from the main clause; in written discourse non-restrictive relative clauses are set off by commas. In this way the speaker indicates that the characterizing event described in the non-restrictive clause is meant as a parenthetical aside. This intonation pattern differs strongly from the uninterrupted flow of restrictive relative clauses," (Radden and Dirven 2007).

Summary: Characteristics of Nonrestrictive Relative Clauses

If this seems like too much to remember about nonrelative clauses—their role, where they appear, and how they function—Ron Cowan provides a helpful summary of their characteristics in his ubiquitous book, The Teacher's Grammar of English: A Course Book and Reference Guide. "The following characteristics distinguish nonrestrictive relative clauses:

- In writing, they are set off by commas. ...
- In speech, they are set off by pauses and falling intonation at the end of the clause. ...
- They can modify proper nouns. ...
- They cannot modify any, every, no + noun, or indefinite pronouns such as anyone, everyone, no one, etc. ...
- They cannot be introduced by that. ...
- They cannot be stacked. ...
- They can modify an entire sentence. ...

The relative pronouns used in nonrestrictive relatives are the same as those used in restrictive relatives, except for that," (Cowan 2008).


  • Cowan, Ron. The Teacher's Grammar of English: A Course Book and Reference Guide. Cambridge University Press, 2008.
  • Denham, Kristin, and Anne Lobeck. Navigating English Grammar: A Guide to Analyzing Real Language. Wiley Blackwell, 2014.
  • Graham, Katharine. Personal History. Alfred A. Knopf, 1997.
  • Preston, Richard. "Flight of the Dragonflies." The New Yorker, 26 Nov. 2012.
  • Radden, Günter, and René Dirven. Cognitive English Grammar. John Benjamins, 2007.
  • Sebold, Alice. The Lovely Bones. Little, Brown and Company, 2002.
  • Shea, Ammon. Bad English: A History of Linguistic Aggravation. TarcherPerigee, 2014.
  • Soni, Saket. "Low-Wage Nation." The Nation, 30 Dec 2013.
  • Updike, John. Self-Consciousness. Random House, 1989.
  • Welty, Eudora. One Writer's Beginnings. Harvard University Press, 1984.
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Nordquist, Richard. "Nonrestrictive Relative Clause." ThoughtCo, Apr. 5, 2023, Nordquist, Richard. (2023, April 5). Nonrestrictive Relative Clause. Retrieved from Nordquist, Richard. "Nonrestrictive Relative Clause." ThoughtCo. (accessed June 6, 2023).