Grammar & Punctuation: Essential and Nonessential Rules

Revised as of
3 Feb 2023

One of the Basic Rules

There are some basic rules in English, and the essential / nonessential rule is critical every time a comma is involved.

Commas separate clauses or phrases that are nonessential to the meaning of a sentence. Of course this rule isn’t hard and fast but can also depend upon the type of clause or phrase and where it is located within the sentence and/or the context. Yes, this is not a clause or a phrase. It’s a rule that applies to clauses or phrases.

An Example of Context

Lebanon R3 Schools provides an excellent example of context with the following sentence: “That man at the football game wearing clown shoes and makeup is my weird uncle.” Or you could say “the clown at the football game is my weird uncle”.

The article notes that the setting is a football game, and it’s reasonable to assume there will be many men at the game. Therefore it is essential that a distinction be made to point out any one particular man. Of course, if we were at a clown convention, it would be essential to note “that clown at the clown convention wearing the red-and-black polka-dotted dress“.

For More Info

For the basics, read “Clauses versus Phrases” with more information about particular clauses in other posts including the dependent clause, the relative clause, the participial phrase, the appositive phrase, and more.

NOTE: One of the irritating aspects of English is how many ways grammarians refer to the same damned term. In this case, essential and nonessential may also be known as defining or nondefining, restrictive or nonrestrictive.

Essential Examples	Nonessential Examples
I will give the document to my brother Tom. The writer has more than one brother. In this case, the specific brother — Tom — is essential information and should not be set off with a comma.	I will give the document to my brother, Tom. The writer has only one brother. The brother’s name is nonessential and therefore set off with a comma.
Nathaniel Hawthorne’s novel The Scarlet Letter has been made into several movies. Hawthorne wrote more than one novel.	Nathaniel Hawthorne’s first novel, Fanshawe, was published anonymously in 1828. Hawthorne had only one first novel.
The guy seated next to me wouldn’t stop talking. Without seated next to me we would have no idea which guy.	Ezra Blung, the guy seated next to me, wouldn’t stop talking. We know who it is, so now the guy seated next to me becomes nonessential.

Grammar Explanations and the Properly Punctuated sometimes . . .

. . . cross as it does here in this post on “Essential and Nonessential Rules”. Being Properly Punctuated — the proper use of quotation marks, commas, semicolons, colons, ellipsis, etc., including how to properly mark dialogue, and more — can be affected by the grammatical rules and principles on structure that determine where and how words are placed in phrases or sentences.

Sometimes I run across an example that helps explain better or another “also known as”. Heck, there’s always a better way to explain it, so if it makes quicker and/or better sense, I would appreciate suggestions and comments from anyone on an area of grammar with which you struggle or on which you can contribute more understanding.

If you found this combination Grammar Explanation and Properly Punctuated post on Essential and Nonessential Rules interesting, consider subscribing to KD Did It, if you’d like to track this post for future updates.

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Essential / Restrictive / Defining
Rule: Indicates that the phrase/clause is important to the meaning of the sentence. It will not be understandable without this clarification and commas should not be used.
Essential THAT			Nonessential WHICH
Rule: That is serving as a restrictive pronoun and does not take a comma.			Rule: Which — when it’s a nonrestrictive pronoun — requires a comma.
John’s cars that are leased are never kept clean. In this case, the dirty cars are specifically those that John leased; John might have non-leased cars that are kept clean.			John’s cars, which are leased, are never kept clean. In this case, all of John’s cars are dirty. The fact that those cars are leased is not essential to the meaning of the sentence. Legend: Yellow indicates the essential Green indicates the nonessential
Adverbial Afterthoughts		Definition: Uses an adverb to tack on additional information that includes specific details.
Return to top or post contents		Rule: When a sentence ends with an adverb that is essential to the meaning of the sentence, the adverb should not be set off with a comma. NOTE: It may however not be essential to the meaning of the sentence, see Nonessential Afterthoughts.
		Legend: Green indicates the adverb We visited Berlin too. We took the train instead.

Nonessential / Nonrestrictive / Non-defining
Rule: Indicates that the phrase/clause is not important to the meaning of the sentence. If it were removed, the sentence would still make sense.
Adjectives Modifying a Noun
Multiple Adjectives		Rule: When you have two or more adjectives — and each independently modifies the noun — you must use a comma. The section on Coordinate Adjectives discusses an easy test on switching adjectives using the conjunction and.
Return to top or post contents		Rebecca’s new dog has long, silky hair. Rebecca’s new dog has long and silky hair. Rebecca’s new dog has silky, long hair. Rebecca’s new dog has silky and long hair.
		The loud, angry protesters mobbed the building. The loud and angry protesters mobbed the building. The angry, loud protesters mobbed the building. The angry and loud protesters mobbed the building.
3+ Modifying Adjectives		Rule: When there are three or more modifying adjectives, it is perfectly acceptable to treat them as a conventional list and include the conjunction and.
Return to top or post contents		It was a long, noisy, nauseating flight. It was a long and noisy and nauseating flight. It was a long, noisy, and nauseating flight.
Sequential Adjectives Do NOT Modify		Rule: If sequential adjectives do not individually modify a noun, they should not be separated by a comma.
Return to top or post contents		He held a bright, red balloon. He held a bright and red balloon He held a red bright balloon.
Repeat Adjective for Emphasis		Rule: When an adjective is repeated for emphasis, a comma (or commas) are required.
Return to top or post contents		It’ll be a cold, cold day in hell before I say yes to you! In a galaxy far, far away . . . That is one bad, bad boy, mm-hmmm.
Appositive Explanation		Rule: When an appositive is used to explain or define, set it off with commas.
Return to top or post contents		Mary Smith, a staff writer at Big City Times, recently wrote a book on that subject. The building’s window placement, referred to by architects as fenestration, is among its most distinctive features. Legend: Green indicates the nonessential explanation
Nonessential Word or Phrase Interrupts		Rule: When a nonessential word or phrase interrupts in the middle of a sentence, it should be set off with commas.
Return to top or post contents		Your work has been, frankly, awful. The hotel, once we finally found it, was very nice. Legend: Green indicates the interrupting word/phrase
Introductory Matter		Rule: When a word or phrase occurs at the beginning of a sentence, a comma should usually separate it from the independent clause.
Return to top or post contents		Legend: Green indicates the introductory matter Yes, we expect to attend the Christmas party. No, you shouldn’t respond to a rhetorical question. Honestly, why would you ever think that? To be honest, I didn’t enjoy the food. In my opinion, the movie was more compelling than the book.
Afterthoughts		Definition: Tacks on additional information.
		Rule: When a word of phrase follows the independent clause at the end of a sentence, it should normally be set off with a comma. NOTE: It may however be essential to the meaning of the sentence, see Essential Afterthoughts.
		Legend: Green indicates the nonessential afterthought I found the painting rather dull, to be honest. You will be joining us for dinner, won’t you? Leave some food for me, please. We will not be attending the reception, however.

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C’mon, get it out of your system, bitch, whine, moan . . . which words are your pet peeves? Also, please note that I try to be as accurate as I can, but mistakes happen or I miss something. Email me if you find errors, so I can fix them . . . and we’ll all benefit!

Satisfy your curiosity about other Grammar Explanations by exploring its homepage or more generally explore the index of self-editing posts. You may also want to explore Book Layout & Formatting Ideas, Formatting Tips, Grammar Explanations, Linguistics, Publishing Tips, the Properly Punctuated, Word Confusions, Writing Ideas and Resources, and Working Your Website.

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Resources for Essential and Nonessential Rules

Some of these links may be affiliate links, and I will earn a small percentage, if you should buy it. It does not affect the price you pay.

“Setting Off Nonrestrictive or Nonessential Information.” “Comma.” The Punctuation Guide.com. n.d. Web. n.d. <http://www.thepunctuationguide.com/comma.html#settingoffnonrestrictiveinformation>.

Straus, Jane. “Essential and Nonessential Elements, Part II.” GrammarBook.com. n.d. Web. n.d. <http://data.grammarbook.com/blog/effective-writing/essential-and-nonessential-elements-part-ii/>.

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Pinterest Photo Credits:

Compound Chocolate is SKopp‘s own work, A Tomato is by Donovan Govan, Cheesecake by Lauren Toyota and John Diemer are courtesy of the Hot For Food Blog, and Diversité taille tomates is Berrucomons own work; all the above are under the CC BY-SA 3.0 licenses. CSA-Striped-Zucchini is Evan-Amos‘ own work and is in the public domain. All of the above are via Wikimedia Commons. Broccoli by Andrea Stöckel is in the public domain, via PublicDomainPictures.net.