Bow-compass

Webster's Dictionary of the English Language

·noun An Arcograph.

II. Bow-compass ·noun A pair of compasses, with a bow or arched plate riveted to one of the legs, and passing through the other.

III. Bow-compass ·noun 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.