Explanation of Blank

Imagine a game of Hold’em where the board on the turn reads as follows.

Board: QT75

It should be evident that there are a large number of straight-draws and flush-draws that players might complete after seeing the river card. Imagine the river comes as follows.

Board: QT752

The river did not complete any possible draw. It’s hence extremely like that the river improved any of the players at the table in a significant way. We hence refer to the river card as being a blank.

Example of Blank used in a sentence -> (Hold’em) we had the flush draw on the turn but had to give up on the pot after the river came a complete blank.

See Also 

River, Turn, Shove