Commas Part 2: More About the Oxford (Series) Comma

Let’s go back to last week’s post about the Oxford comma. The Oxford comma is, of course, the comma used — or not used — before the last item in a series.

I believe all the examples given in that last post were series of words. However, not all series are made of just single words. We can have a series of phrases, a series of dependent clauses, or even a series of sentences. Here are some examples:

Series of Phrases (a phrase is a small group of related words) :

• The small boy ran out of the house, across the street, and to the neighbor’s house. (The Oxford comma is used before the and.)

Series of Dependent Clauses (a dependent clause is a group of words that has a subject and a verb but is not a complete sentence):

• Nothing looked as beautiful and peaceful as our neighborhood after the storm was over, before the street was plowed, and when the moon came up. (Oxford comma is used before the and.)

Series of Sentences. You may not do it often, but there are times when you may want to connect a group of sentences.

• I graduated from The University of California at Santa Barbara, my brother graduated from UCLA, and my sister is currently a student at the University of Arizona.  

 If you look at the last example, you will see that there are three complete sentences in that one sentence. To me, the Oxford comma really makes all the above examples sentence clearer. But remember, even with these other types of series, the final comma before the conjunction — the Oxford comma —  is not required. 

If you are going to string a few sentences together into one longer sentence, it is easier if each sentence is pretty simple, like the ones in the above example. If you have more complicated sentences, perhaps with commas already within them, you will want an alternative to stringing them together with commas. You will need to use semicolons, perhaps, or rewrite — but that is another blog post.

What if you have a vertical list? You have the option to set up a vertical list the same way you set up a sentence (horizontal list, or series), with or without the Oxford comma –or you can do it another way, without commas. Let’s take a look at a vertical list.

1. The ingredients are

• 3 eggs, 
• 2 cups of milk,
• 1 tablespoon of butter, and
• 2 ounces of chocolate.

You can, or course, eliminate the Oxford comma, as in the following example.

2. The ingredients are

• 3 eggs,
• 2 cups of milk,
• 1 tablespoon of butter and
• 2 ounces of chocolate.

And of course, you can eliminate the commas and the conjunction and altogether.

3. The ingredients are

• 3 eggs
• 2 cups of milk
• 1 tablespoon of butter
• 2 ounces of chocolate

In the first two list examples, I used a period at the very end because the whole list is really a sentence if you read through it. If you are going to write it with the commas and the conjunction, you should also include the period at the end. In the third example, I used no punctuation. You could put a period after each item in example 3 because each item completes the sentence, “The ingredients are . . .” But no,  you don’t have to.

So a series in a sentence is actually a list, but a horizontal list rather than a vertical one. And a series doesn’t have to be just single words. A series can be made up of phrases, clauses, or complete sentences too. The Oxford comma is used the same way in these types of series. And again, it is optional, but I prefer to use it.

Oh, wait. You want to put a colon after “The ingredients are”? Technically it isn’t correct because the sentence doesn’t end there, so you don’t want to put a full stop there with a colon. The list items complete that thought. Can you use a colon? I have seen it done. People like to introduce

lists with colons. If the introduction is a complete sentence, then you do use a colon. For example, if the introduction had said, “The ingredients are as follows,” you would use a colon (or a period). 

The ingredients are as follows:

But we digress . . .

Stay tuned for Commas Part 3: What About Compound Sentences? next week.