Commas with Nonrestrictive vs. Restrictive Elements

What do the grammar terms nonrestrictive and restrictive mean? And which requires commas?

The Short Story

Nonrestrictive: Describes a noun, phrase, or clause that serves as additional but not necessary information in a sentence. Removing it would not change the meaning of the sentence. Nonrestrictive elements should have a comma before and after them.

Restrictive: Describes a noun, phrase, or clause that serves as necessary information in a sentence. Removing it would change the meaning of the sentence and cause confusion. Restrictive elements should not have a comma before or after them.

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The Novel

Why should writers care about the terms nonrestrictive and restrictive?

These grammar terms and the punctuation rules that go along with them actually make a huge difference in helping readers understand your writing. 

Commas, especially nonrestrictive and restrictive commas, add clarity to your sentence's meaning. So, if you put one in the wrong place or forget one completely, there's a chance your readers could be confused.

Additionally, because nonrestrictive elements are punctuated differently from restrictive elements, knowing which is which streamlines the editing process tremendously. As writers, you can know when and when not to use commas.

What is the difference between nonrestrictive and restrictive elements?

Both nonrestrictive and restrictive elements are discussed in The Chicago Manual of Style 6.29. The biggest difference between the two is that one uses commas and one does not. But before we get into that, here are some preliminary basics.

The terms nonrestrictive and restrictive can describe one of three grammatical categories:

Noun: A person, place, or thing referred to in a sentence.

Ex. She called Ella and her mom on the phone. 

Ella, mom, and phone are all nouns.

Phrase: A word or group of words that forms a function in a sentence.

Ex. She called Ella and her mom on the phone.

On the phone is a phrase adding information to the verb. It is specifically an adverbial phrase.

Clause: A group of words containing a subject and a predicate. (A predicate is a part of a sentence that contains both a verb and information about the subject.)

Ex. She called Ella and her mom on the phone.

She called Ella and her mom is a clause in this sentence.

If a noun, phrase, or clause is restrictive, this means that it cannot be taken out of the sentence without changing the meaning. In essence, the sentence is as simple as it can be and thus “restricted” to its current form.

The examples of nouns, phrases, and clauses above are all restrictive. Taking out either of the nouns Ella or mom would change the sentence’s meaning to her only calling one person. Taking out the phrase on the phone would make it unclear if she called on the phone, or on an intercom, or just loudly. And removing the clause would of course leave us without a sentence at all.

If a noun, phrase, or clause is nonrestrictive, this means that it could be taken out of the sentence and the main sentence would still carry its original meaning. Keep reading to see examples.

How can you tell if an element is nonrestrictive or restrictive?

To know if a noun, phrase, or clause is nonrestrictive, ask whether the words could be taken out without losing the intended meaning. 

Here are examples of nonrestrictive and restrictive nouns:

Nonrestrictive: You should search for Jess Jefferies’s debut book, Thirteen-Year Crush.

Restrictive: You should search for Jess Jefferies’s book Thirteen-Year Crush.

The first sentence refers specifically to the author’s first book, and the title is extra information. The debut book would be the same regardless of whether the book title is mentioned, so the noun is nonrestrictive. However, the second sentence would not refer to any specific book without referencing the title (because Jess Jefferies has written more than one). Thus, the book’s name is restrictive.

NOTE: Let’s say the author Jess Jefferies had only written one book. That would make the title in the second sentence nonrestrictive because the sentence could not be referring to any other book if there’s only one.

Here are examples of a phrase used as nonrestrictive first and restrictive next.

Nonrestrictive: Did you get rid of The Sword in the Stone, the book with the torn cover?

Restrictive: Did you get rid of the book with the torn cover?

In the first sentence, it is clear which book is being referenced even without knowing that it has a torn cover. The phrase the book with the torn cover can be omitted from the sentence. This means that the clause is nonrestrictive. In the second sentence, there would not be a complete sentence without that phrase, so it is restrictive.

Finally, here are examples of nonrestrictive and restrictive clauses:

Nonrestrictive: She can’t wait to meet Mick Jagger, who sang for the Rolling Stones.

Restrictive: She can’t wait to meet the lead singer who sang for the Rolling Stones.

To check for nonrestrictive or restrictive, take out the information that comes after the who in both of these sentences. The first sentence doesn’t need additional context to get the writer’s meaning across, while the second sentence does. Without the clause who sang for the Rolling Stones in the second sentence, the reader would have no idea who the lead singer is.

Do restrictive or nonrestrictive elements need commas? 

If you were carefully observing the difference between nonrestrictive and restrictive elements, you probably already figured out that one of them uses commas and one doesn’t. 

Here’s the answer: 

Nonrestrictive elements (those that can be removed from the sentence) should be preceded by a comma if they appear in the middle or at the end of a sentence and followed by a comma if they appear in the middle or at the beginning of a sentence. Think of the commas as hooks that lift out the part of the sentence that is extra information.

An example of this would be the sentence, “His boss, Mr. Jensen, retired.” The nonrestrictive element is Mr. Jensen and is surrounded by commas. Those commas are shown in the graphic as hooks lifting that portion of the sentence out. If that extra information is taken from the sentence, what’s left is now restrictive: “His boss retired.” Restrictive elements should never be preceded by or followed by a comma.

Just remember that commas surround what’s not essential to a sentence, and you’ll be punctuating your nouns, phrases, and clauses correctly. And of course, we will double-check for you in our copyedit!