Dark

1. An action declared by a player first to act after the current betting round closes, but before the next card or cards are dealt.

Explained

An example would be in a hand of Texas Hold'em, the cutoff raises and it folds over to the big blind who makes a call. Before the flop is dealt, the big blind would then say "I check in the dark". That action would mean that this player automatically checks and action goes to the cutoff.

David Williams in the Dark