The Oxford comma appears in lists, just before the last item.
The Oxford comma is a point of contention in the English-speaking world. While punctuation in English leads to much debate in general, the Oxford comma sharply divides the world into those who love it and those who hate it.
What is the Oxford comma?
Have a look at this often-used quote:
‘You can have my Oxford comma when you pry it from my cold, dead, and lifeless hands.’
Notice the comma before ‘and’? That is the Oxford comma (also known as the serial comma). Obviously, this passive-aggressive text is from the pro-Oxford comma camp.
The Oxford comma is ‘an optional comma before the word “and” at the end of a list’. This definition is from Lexico. Note the term ‘optional’. That is precisely the reason for all the debate and confusion over this tiny squiggle.
The name itself is a reference to the house style of Oxford University Press. The UK-based publisher has used the serial comma consistently for a hundred years. Yet, this comma is used far more frequently in American English than in British English.
Advantages of using the Oxford comma
To begin with, there can be confusion when you do not use it. Consider this example:
‘At the coffee shop, Roger met Aunty Flo, an old soccer coach and a drug dealer.’
The confusion here is whether Roger met one person or three people. You might assume that Aunty Flo is an old soccer coach and that she moonlights as a drug dealer. Now look at what happens once you introduce the Oxford comma:
‘At the coffee shop, Roger met Aunty Flo, an old soccer coach, and a drug dealer.’
This makes it clearer that Roger met three people: (1) Aunty Flo, (2) an old soccer coach, and (3) a drug dealer.
Here is another example:
(a) ‘Roger ordered coffee, cookies and macaroni and cheese.’
(b) ‘Roger ordered coffee, cookies, and macaroni and cheese.’
Here, the serial comma appears after ‘cookies’ because ‘macaroni and cheese’ represents one item. By introducing the comma here, a clear demarcation is made between the last two items on the list.
Bottom-line
Remember, this is optional. Whether or not you use the Oxford comma comes down to personal choice and the style guide you need to follow. But it does remove ambiguity, and clearer sentences are always a good thing.
