Definition
A straight draw missing the first or last card of the sequence that would complete the straight. For example, the player holds 3h 4c and the flop is 2h 5d 8h. The player has an open-ended straight draw with 2h 3h 4c 5d, and to complete the straight he needs either an A or a 6, 8 outs in total (4 aces and 4 sixes). The probability that an open-ended straight draw completes from the flop to the river is 31.5%.