Definition of dry
When we speak of dry (sec), we generally speak of flop dry (an flop dry opposing an flop wet). A dry means that an flop (or table) does not offer an obvious draw. The classic example of a "dry board" is A-7-2 rainbow (with three different colors, let's say heart, clover and spades, so it offers no color print). The flops with doublets will also be flops dry (2-2-6 for example, with no color print).
How to play an flop dry?
The flops dry must be played in a different way than the flops 15. Especially if you have a very strong hand. If you have AA on the flop we suggested above (A-7-2 without flush draw), you are probably better to play passively. Your opponent will have almost no reason to call your bet and you may lose it. On the other hand, if you have a bluff on A-7-2, you may be more successful since your opponent will not call with a draw and unless he has the top pair or better (a minority of the time), he will be forced to fold. And finally, as a general rule, there will be less bluffing and semi-bluffing on this type of board. When your opponent shows strength, unless there are notes to the contrary, give him credit.