bracket
n.An L-shaped bookend or brace.The typographic characters [ ], < >, and { }.v.To surround.To create a short sequence of photographs, each with slightly different exposure.
Notes
Brackets2 are frequently described as square ([ ]), angle (< >), and curly ({ }) brackets. Curly brackets are also called braces. - Photographers will often bracket4 a shot if they are uncertain of the proper exposure or if the light conditions are extreme. The multiple versions provide some insurance that at least one exposure will create a useful negative.