What does "compasses" mean?

Compasses: 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. Note: The compasses for drawing circles have adjustable pen points, pencil points, etc.; those used for measuring without adjustable points are generally called dividers. See Dividers. Bow compasses. See Bow-compass. -- Caliber compasses, Caliper compasses. See Calipers. -- Proportional, Triangular, etc., compasses. See under Proportional, etc.