%bow-compass%

n.; pl. Bow-compasses 1. An arcograph. [ 1913 Webster ]

2. A small pair of compasses, one leg of which carries a pencil, or a pen, for drawing circles. Its legs are often connected by a bow-shaped spring, instead of by a joint. [ 1913 Webster ]

3. A pair of compasses, with a bow or arched plate riveted to one of the legs, and passing through the other. [ 1913 Webster ]