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 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.