In poker, a backdoor is referred to as a backdoor draw. This is a semi-prepared combination that requires catching outs on the turn and the river in order to win. Some new players might fold such a hand, while others would overestimate their chances of winning the pot and decide to draw.
As a rule, they discuss backdoor straight draws and backdoor flush draws. The term “runner-runner draw” may be used interchangeably.

Obstacles in Poker Backdoor Odds Calculation
It’s important to keep in mind that the concept by which outs are computed does not apply to the assessment of the odds of upgrading the backdoor. To determine the number of outs, just one card is used, but two are used to determine the backdoor.
In order to account for the possibility of a backdoor, some poker players add one percent to the standard deviation of the odds of upgrading one’s hand. As individual backdoors have initially larger possibilities of constructing a full combination, this method is not always able to display the true picture. The odds of making a combination may actually go down in certain situations, since some cards can’t be used because they overlap with outs.