n.
    - each of a pair of marks ( ) [ ] { } < > used to enclose words or figures and separate them from the surrounding context.
 - a category of similar people or things.
 - a right-angled support projecting from a wall, holding a shelf, lamp, etc.
 - Military  the distance between two artillery shots fired either side of the target to establish range.
 
v.
 (brackets, bracketing, bracketed)
    - enclose (words or figures) in brackets. 
▸Mathematics  enclose (a complex expression) in brackets to denote that the whole of the expression has a particular relation to another expression.
 - place in the same category.
 - attach by means of a bracket.
 - Military  establish the range of (a target) by firing preliminary shots short of and beyond it.
 
 
  Etymology
  C16: from Fr. braguette or Sp. bragueta ‘codpiece, bracket, corbel’, from Provençal braga, from L. braca, (pl.) bracae ‘breeches’.