English Student Study Guide: The Oxford Comma Explained

oxford comma graphic

Few topics get grammar enthusiasts more riled up than the Oxford comma. As an English student, you may already have a firm stance on this controversial piece of punctuation. Or, you might be wondering what the fuss is about. Let's take a look at what exactly the Oxford comma is, and why some consider it such a big deal.

What is the Oxford Comma?

The Oxford comma, also known as the serial comma, is the last comma used in a series of three or more items and comes before the conjunctions "and" or "or." Here are some examples of sentences that use the Oxford comma:

She always wanted to visit Germany, France, Spain, and Portugal.

He could never decide if his favorite meal was breakfast, lunch, or dinner.

Notice the commas that come after the words "Spain" and "lunch." Those are examples of the Oxford comma. This controversial character will always come immediately after the second-to-last item in a list, before the final "and" or "or." 

A sentence written without an Oxford comma simply omits the character in that last location:

She always wanted to visit Germany, France, Spain and Portugal.

When to Use the Oxford Comma

In everyday writing, the Oxford comma is considered optional. As an English student or writing professional, however, you should always ask if there's a particular style you're required to follow to find out if the Oxford comma is expected of you. 

Certain style guidelines explicitly call for consistent use of the Oxford comma. The Chicago Manual of Style is a noted Oxford comma proponent, as is the MLA Style Manual and Oxford University Press – in fact, that's where the serial comma gets its proper-noun nickname. 

Other style guides restrict the use of the Oxford comma, except in special situations that are covered below. The most prominent of these guides is the Associated Press Stylebook, commonly known as AP Style. Journalists, public-relations practitioners, and other media outlets usually follow AP Style, which is regarded as the foundational guidebook for news writing in the US. 

Individual schools or organizations may proscribe their own style guidelines or exceptions, as well. Many prominent publications and businesses still use the Oxford comma, even though they adhere to AP Style otherwise. Check with your school to find out which style they prefer. 

One of the most important lessons you can learn about the Oxford comma is that consistency counts. Learning and sticking with a specific style is important for any college student, but especially so for English majors. You want to demonstrate that you have the grammatical knowledge and discipline that's expected of wordsmiths by using the same rules every time you write.  

Using the Oxford Comma for Clarity

One of the main arguments in favor of using the Oxford comma is that it can help prevent confusion or ambiguity in a sentence. Consider the following sentence, written without an Oxford comma:

Jeff introduced me to his brothers, Lucille and Alice.

This sentence can be read two ways: either Jeff has two brothers named Lucille and Alice, or the speaker was introduced to Jeff's brothers in addition to Lucille and Alice. The Oxford comma could easily clear up the confusion:

Jeff introduced me to his brothers, Lucille, and Alice.

The Oxford comma can also prevent confusion when one or more of the separate items in a list includes the word "and" or is exceptionally long. In these cases, using the Oxford comma keeps these separate items from running together: 

All I would eat as a kid was hot dogs, macaroni and cheese, and peanut butter and jelly.

The comma after "cheese" in this example makes it clear that "peanut butter and jelly" are a single unit separate from "macaroni and cheese." Even in styles like AP, where the Oxford comma is not otherwise used, a serial comma can be employed when there are internal uses of the word "and" in a series or the things being listed contain long phrases or ideas.

Something as small as a single comma can seem inconsequential at first, but when it comes to writing, the Oxford comma can make a big difference in terms of your meaning. For English students, understanding when and why to use it could literally be part of your future career. Now that you know more about the elusive Oxford comma, you might never look at that little curved line the same way again.

Written by Ashford University staff

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