Dictionary
se'ries com"ma
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. Also called
serial comma. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.