What is an Oxford Comma

The Oxford comma is heavily debated in literary circles. Learn what is an oxford comma and how you should use this controversial punctuation mark here.

The Oxford comma is also called a Harvard comma or serial comma and is a punctuation mark in the American English language that is used before the last item at the end of a list. When writing a list of things, the Oxford comma is used to differentiate between two items on a list that might be linked to one another if using a regular comma.

Technically, grammar rules don’t prohibit using either a series comma or a regular comma in a list of things, so it’s up to the writer and, more specifically, the editorial preferences of the publication featuring the writer’s content. But knowing when to use a serial comma and when not is still a mystery, even to well-established writers and content creators.

Examples of the Oxford Comma

Here are some examples of sentences that use the Oxford Comma:

  • “My favorite authors are Stephen King, Charles Dickens, Suzanne Collins, and Ayn Rand.”
  • “I have a few rock bands on my playlist, like Vampire Weekend, Arcade Fire, and Cage the Elephant.”
  • “Will you travel to the Middle East, the United Kingdom, or America?”

Examples of a Regular Comma

The following examples are of how a regular comma may be used, which may look like there’s a missing comma where the last comma would be in sentences using Harvard commas.

  • “In my opinion, the best book on punctuation is Eats, Shoots & Leaves.”
  • “I’m currently using four social media platforms — Twitter, Facebook, Instagram and LinkedIn.”
  • “For dessert, I’m having chocolate pie with caramel sauce, whipped cream and a cherry on top.”

Does Using a Serial Comma Change the Meaning of a Sentence?

In some cases, the lack of a comma in a list of things can change the meaning of a sentence enough that the sentence cannot be understood to mean what the writer intended. Here are a few examples:

  • “At the bakery, there were many different flavors of cupcakes, like coconut, chocolate, and strawberry and vanilla.”
  • “Thank you to my parents, Linda and Bob.”

In the first example, a reader might misconstrue that there are only three flavors of cupcakes: coconut, chocolate, and a combination of strawberry and vanilla when the writer intended to convey that there are four flavors of cupcakes: coconut, chocolate, strawberry, and vanilla. In the second example, the lack of an Oxford comma may make it impossible to determine if the speaker is thanking their parents and two people named Linda and Bob or if the speaker is thanking their parents Linda and Bob. In both cases, the missing comma allows the reader to interpret the sentence differently, leading to confusion.

The Oxford Comma Lawsuit

There’s one such case where a missing serial comma cost a Maine dairy company millions of dollars. In February of 2018, delivery drivers for Oakhurst Dairy in Portland were awarded $5M in a class action lawsuit. The company elected to settle the claim, which alleged that the lack of a comma before the last item in a list changed the meaning of state law, entitling them to four years of back overtime pay. While a scenario such as this is scarce, it illustrates just how critical that final comma can be to interpret the meaning of a sentence in some cases correctly.

How Different Style Guides Make Use of the Oxford Comma

What is an Oxford Comma?
The Oxford University Press still encourages writers to use serial commas to separate items in a list.

Which type of comma you use in a piece of content largely depends on the preferences of the style manual of the publication you’re writing for. However, here are how some of the most common and well-known stylebooks use commas:

  • The New York Times. The New York Times style guide discourages using serial commas except when necessary for clarity.
  • The Modern Language Association (MLA). The Modern Language Association (MLA) allows writers to use the Oxford comma.
  • The Economist. The Economist does not use the Oxford comma.
  • The Associated Press Stylebook (AP Stylebook). The Associated Press Stylebook prefers that writers do not use a Harvard comma unless one is necessary to prevent the misreading of a sentence, clause, or phrase.
  • The American Psychological Association (APA). The American Psychological Association (APA) requests that writers use a serial comma before the last item in a list of things unless the writer intends for two items in the list to be correlated.
  • Oxford University Press. The Oxford University Press still encourages writers to use serial commas to separate items in a list.
  • The Chicago Manual of Style. The Chicago Manual of Style permits and encourages the use of the Oxford comma.

Writers who are unsure of whether or not the publication for which they are writing permits the use of serial commas should contact their editors and ask which comma style is preferred or allowed. Many publications permit writers to use whichever comma type results in the easiest-to-read sentence, but it’s important not to assume. You don’t want to submit a piece of content riddled with Oxford commas if the publication has a strict policy against them.

Final Thoughts About the Oxford Comma

The Oxford comma can be extremely helpful in ensuring a clear difference between items in a list, even if those things correlate or connect in some way. Always check the style guide or reach out to the editor of a publication you’re writing for to find out whether or not the use of the Oxford comma is allowed or prohibited. If you are still unclear, default to the comma style that makes the sentence easiest to read.

Looking for more? Check out our serial comma vs. oxford comma guide.

FAQs About What is An Oxford Comma

Which apps are the best for checking grammar online?

An online grammar checker or grammar editor app can help you scan your written content for missing commas, punctuation mark errors, spelling errors, and more that can easily be missed even with the most thorough editing. Many grammarians use Grammarly, which functions as a browser extension and allows users to check their grammar in almost any input field.

When should you use a semicolon instead of a comma or commas instead of a semicolon?

Semicolons are used instead of a comma or a period when neither would be appropriate. For example, you may use a semicolon when you want to connect the ideas in two separate sentences together without ending the first sentence. However, you still want some distinction between two phrases that using a comma would eliminate.

What is an apposition?

An apposition is a noun phrase where two independent and grammatically parallel clauses are placed next to one another, with the second clause identifying the first clause differently. Here are some examples of an appositive phrase:

1. “Joseph’s favorite teacher, Mrs. Catsnake, sent him home with a lot of homework this weekend, so he might not like her as much anymore.”
2. “My dog, an energetic Siberian Husky and Alaskan Malamute mix has to be taken on long walks or runs a few times a day, so he doesn’t get antsy and end up destroying the house.”
3. “The doctor, a specialist in heart conditions, recommended that I take medicine to control my high blood pressure.”

What is a coordinating conjunction?

A coordinating conjunction is a type of conjunction that connects phrases, words, or clauses to one another, like “for,” “but,” “yet,” and “and.” The Oxford comma is used in phrases containing coordinating conjunctions to inform the reader that although two items in a list may be alike or belong together, there is still a separation or distinction between them.

If you still need help, our guide to grammar and punctuation explains more.

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