The serial comma is a comma that comes before the final item in a list of three or more items. It comes before the conjunction (“and” or “or”): “John, Mandy, and Lupita.” Without the serial comma, the same phrase would be “John, Mandy and Lupita.”
The serial comma is optional; different style guides have different recommendations. But most academic style guides do recommend using it consistently.
The serial comma is also called the Oxford comma or the Harvard comma.
The Oxford comma (a comma placed before the final item in a list of three or more items) is optional. It is not an error to leave it out. “Salt, pepper, and vinegar” and “salt, pepper and vinegar” are both grammatically correct.
Different style guides have different recommendations about using it. Most academic style guides (e.g., APA, MLA, Chicago) recommend using the Oxford comma consistently, so this is typically the best approach in academic writing.
Note that the earlier commas in a list are not optional: “salt pepper and vinegar” is not grammatically correct.
There’s no difference between the serial comma and the Oxford comma. They’re two different names for the same thing: a comma before the conjunction (“and” or “or”) in a list of three or more items (e.g., “ham, cheese, and tomato”).
The Oxford comma or serial comma is optional but recommended by most academic style guides. It’s sometimes also called the Harvard comma.
The comma before “and” (or comma before “or”) at the end of a list is optional. It’s referred to as an Oxford comma or serial comma. Most academic style guides recommend adding it (“salt, pepper, and paprika”). But it’s also not a grammatical error to write a list without it (“salt, pepper and paprika”). Some authorities, such as the AP Stylebook, do recommend leaving out the comma.
The Oxford comma tends to improve the clarity of lists, especially complex lists, by showing clearly where one list item ends and another begins. In academic writing, it’s recommended to use it.
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