The Serial Comma Explained

Welcome to ask the editor. I'm Emily Brewster, an associate editor at Merriam-Webster.

We all know that commas separate items in a list. I love nouns, verbs, adjective, and adverbs. But that last comma is shrouded in controversy.

Is it necessary?

There is several names for the comma that separates the second to last item in a list from a final item that is introduced by and or or. It's most commonly called the serial comma. It's also called the Harvard comma and the Oxford comma because it is used by the publishers associated with those universities.

The serial comma is optional.

Publishers typically take a stand on whether or not to use it, and writers tend to feel strongly one way or the other. It is up to you, but be aware that not using the serial comma can result in some ambiguity.

There is the likely fictitious example of a book dedication:

I would like to thank my parents, Ayn Rand and God.

where without the comma it sounds like Ayn Rand and God are the ones who begot the author.

And then there is the real example from text about a documentary on the late Merle Haggard:

Among those interviewed, were his two-ex-wives, Kris Kristofferson and Robert Duvall.

In many cases though, no ambiguity arises:

The house has a big yard, small kitchen and few windows.

The recipe calls for sugar, butter, cream, salt and vanilla.

Like the serial comma? Use it, or not.

Newspapers have traditionally done without it as a way to save space. Dictionaries have also traditionally been concerned with space, but we at Merriam-Webster use the serial comma. No one calls it the Merriam-Webster comma, but if people started to we wouldn't object.

For more Ask the Editor videos, visit merriam-webster.com.