series comma

noun

1. a comma used after the next-to-last item in a series of three or more items when the next-to-last and last items are separated by a conjunction. In the series A, B, C, or D, the comma after C is the series comma.

Example Sentences

Dreyer is a VP and copy chief at Random House, not to mention the unofficial language guru on Twitter, where he dispenses grammar bon mots such as: “Only godless savages eschew the series comma.”

From Washington Post