doubleton definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
two playing cards of the same suit that are the only cards of that suit in a hand dealt to a player
doubleton definition by American Heritage Dictionary
A pair of cards that are the only ones of their suit in a hand dealt to a player.
Origin: double + (single)ton.