Backdoor

Making a hand other than the one intended. Example: Having J/10 of Clubs with a flop of A of Clubs, 5 of Clubs. 6 of Spades. The turn and river are K & Q of Hearts. You made a straight instead of the intended (and more likely) flush.

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W