A freely pivoting circular disk carrying the magnetic needles of a compass and marked with the 32 points of the compass and the 360 degrees of the circle.
The circular card mounted on a free pivot inside a compass and marked with the points of direction and, often, the degrees of the circle.
Compass-card Sentence Examples
It is said that the idea of a liquid compass was suggested to Crow -by the experience of the captain of a coasting vessel whose compass card was oscillating wildly until a sea broke on board filling the compass bowl, when the card became steady.
When, and by whom, the compass card was added is a matter of conjecture.