The serial comma comes before the final conjunction in a list. Learn when you must use it.
The Bottom Line on Serial Commas
Finally, there are similar sentences where even a serial comma doesn't make the meaning clear. Consider this sentence: I went to see Zack, an officer and a gentleman.
Without the serial comma—I went to see Zack, an officer and a gentleman—it could mean that Zack is both an officer and a gentleman, or that I went to see three people: Zack, an unnamed officer, and an unnamed gentleman.
With the serial comma—I went to see Zack, an officer, and a gentleman—it could still mean two different things. It could mean I went to see three people (Zack, an unnamed officer, and an unnamed gentleman), or it could mean I went to see two people (Zack, who is an officer, and an unnamed gentleman).
So, the bottom line is that using the serial comma is a style choice. Most publications except newspapers favor using it all the time, as do I, and all publications call for a serial comma when leaving it out could cause confusion. And sometimes sorting out your meaning is just too much for one little comma and the best option is to rewrite your sentence.
* I am aware that the final preposition could be left off the end of this sentence without changing the meaning. I considered leaving it off, but decided to write it this way because the timing is better when it is read aloud.
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7. The American Heritage Guide to Contemporary Usage and Style. Boston: Houghton Mifflin, 2005, p. 100.
8. “What is the Oxford comma?” Ask Oxford.com http://tinyurl.com/4b8d6 accessed July 8, 2007).
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