Backdoor Flush Draw in Poker

A backdoor flush draw needs both the turn and river to supply the required suit. On the flop, a Hold'em player has three cards of that suit across their hole cards and the board. One matching card alone will not complete the flush.

Example of Backdoor Flush Draw:
You hold the ace and queen of spades on a jack-spade, seven-heart, two-club flop. A spade on both the turn and river completes your flush.