doubleton

From double +‎ -ton.

doubleton (plural doubletons)

1. (mathematics, rare) A set containing precisely two elements.
2. (bridge) A pair of cards of the same suit, which are the only cards of that suit in a player's hand
   • 2009 January 8, Phillip Alder, “Part 1 of an Experiment, Ending in a Trump Coup”, Bridge, in New York Times‎^[1]:

     If she had had the doubleton ace of diamonds and a low club, she would have made a four-club splinter bid, showing four-card spade support, the values for game and a singleton or void in clubs.

• singleton

• Glossary of contract bridge terms on Wikipedia.Wikipedia