Compasses

n.
  1. An instrument for describing circles, measuring figures, etc., consisting of two, or (rarely) more, pointed branches, or legs, usually joined at the top by a rivet on which they move.
    2. Bow compasses .
    See Bow-compass.
    Caliber compasses, Caliper compasses .
    See Calipers.
    Proportional, Triangular, etc., compasses .
    See under Proportional, etc.