Math Goodies defines a math compass as an instrument used to draw circles. According to Maths Teacher, it can also be used to draw parts of circles called "arcs."
According to Maths Teacher, a compass consists of two movable arms hinged together. One arm has a pointed end, called a compass needle, that holds the compass in place, while the other holds a pencil to draw the circle.
To draw with a compass, take a tight hold of the pencil and hinge so they do not slip. Align the pencil lead with the compass needle and press down on the pencil. Then turn the knob at the top of the compass to draw a circle or arc.