Blank
A Blank is the name given to any board card that doesn't appear to affect the standings in the hand.

For example, if there has been a significant amount of pre-flop raising resulting in only two players reamining in a hand, you would generally consider that both remaining players hold premium starting hands, such as AKs or high value pocket pairs. In this instance a flop of two, three, seven with no matching suits would be considered to be all 'blanks'.