hands
Backdoor draw
Also: backdoor, runner-runner, backdoor flush draw
A draw that needs both the turn and the river to complete — for example three cards to a flush on the flop. Backdoor draws add a few percentage points of equity and make hands worth continuing with.
Example. Holding J♦9♦ on K♦-7♠-2♦ you have a backdoor flush draw; the turn 4♦ gives you a real flush draw.
A backdoor flush draw comes in about 4% of the time and a backdoor straight draw slightly less, but their real value is strategic: they give you more turn cards on which you can keep betting or improve to a real draw. Solvers routinely pick backdoor hands to float or bluff with. 'Runner-runner' describes the situation where such a draw actually gets there.