In archaeology, a blank is a thick, shaped stone biface of suitable size and configuration for refining into a stone tool. Blanks are the beginning products of lithic reduction, and during prehistoric times were often created for trade or later refinement at another location. Blanks were often formed through the initial reduction of lumps of tool stone at simple quarries, often no more than easily accessible outcroppings of the local tool stone (although this was certainly not the case at Grimes Graves in England). Sometimes the shape of the blank hints at the shape of the final tool it will become, but this is not always the case. A blank may consist of either a large, unmodified flake or a reduced core, often with a rough subtriangular or lanceolate shape. Rough chopping tools, derived by removing a few flakes along one edge of the cobble, can also be considered to fall into this group.
A blank is also an important tile in the game of Scrabble. Rather than having one of the letters of the alphabet printed on it, it has a blank face and can be substituted for any letter you desire (comparable with the wild card or joker in card games, or with a wildcard character in telecommunication and computing). While you gain no points for playing a blank, it can enable the use of other tiles from your hand that would be otherwise useless.
A blank is also a type of cartridge for a gun that contains gunpowder but no bullet or shot. Blanks are commonly used for safety reasons in military training maneuvers, in movies that require gun fights and in starter's pistols to signal the beginning of races. However it should be noted that given the speed of a blank cartridge they are by no means safe. Also they can cause damage to the eardrum.
A blank expression is either one of slight confusion when someone refers to something which you do not understand or a poker-face (shortened to a po-face) where you which to hide your expression from other people. In poker you do not want people to know if you are holding a good or bad hand, hence the need for a blank expression.
