serial comma (thing)

Also known as the Harvard comma.¹

In the English language, this is the comma that comes before the conjunction in a phrase that lists items serially. E.g.:

• The three primary colors are red, blue, and yellow.

The comma just after the word "blue" is the serial comma.

1. The implication here is that the comma is superfluous and snobbish.²
2. I always use one, which is probably tiresome of me, but then I am superfluous, snobbish, and a holder of a degree from Harvard.³
3. See! I did it again.