D'Alenbert System - A scoring plan in which one unit is added for a losing bet and one subtracted for a winning bet.

Deal - To give out the cards during a card game.

Dealer - Casino employee who deals. Sometimes called the Banker.

Deuce - A two in dice.

Dice - Two identical numbered cubes.

Die - Singular for dice.

Dime - A $10 chip.

Dime Bet - A $1,000 bet.

Discard Tray - A tray for cards played or discarded, near the dealer.

Dollar Bet - A $100 bet.

Don't Come Bet - In Craps, the same as a Don't Pass Bet, except that it is placed after the initial Come Out Roll.

Don't Come Line - In Craps, the area of the table where a Don't Come Bet is placed.

Don't Pass Bet - In Craps, a bet placed before the initial Come Out Roll, betting that a seven will be rolled before the Point is repeated.

Don't Pass Line - In Craps, the area of the table where a Don't Pass Bet is placed.

Double Down - A betting option in Blackjack allowing the player to receive one card, and only one card, to try to beat the dealer. If the player's hand beats the dealer's, the player receives double his original wager.

Double Up - Gambling tactic in which the player doubles his bet after a loss in order to try to win back his or her money. Sometimes called the Martingale System.

Down Card - A card that is face down.

Down to the Felt - Out of money, broke. Slang.

Draw - To draw a card to complete a hand. Usually used in poker games.

Drop - Money lost while gambling.

Drop Box - On a table, the box used as a kind of safe for cash, chips, and markers.