a. In Building, a piece of stone, wood, or metal projecting from a wall, and having a flat upper surface which serves as a ledge to support a statue, the spring of an arch, a beam, shelf, etc.; usually carved or sculptured, and sometimes employed merely as a decoration; under the name of bracket are included the corbel n. and the console n.

b. A small (usually ornamental) shelf, or set of two or three shelves, for the wall of a room.

c. transferred (? with allusion to bract n.)

a. One of two marks of the form [ ] or ( ), and in mathematical use also {}, used for enclosing a word or number of words, a portion of a mathematical formula, or the like, so as to separate it from the context; in typography, esp. applied to ‘square brackets’ (formerly called crotchets), the ‘round brackets’ being designated ‘parentheses’. Sometimes also applied to the ‘vinculum’ or horizontal line over the writing, serving in algebra the same purpose as brackets; also to the ‘brace’ { used for coupling together two lines of writing or printing (cf. bracket v.); hence brackets is used figuratively for ‘the position of being bracketed equal, equality’.

b. transferred. The (specified) distance between a pair of shots fired, one beyond the target and one short of it, in order to find the range for artillery; chiefly in the phrase to establish a bracket.

c. A group bracketed together as of equal standing in some graded system, as income bracket: a class of persons grouped according to income.

d. Skating. A series of turns resembling a bracket or ‘brace’ (see sense 5). Also attributive.