Generic term to indicate an instrument used to measure distances and draw circumferences. It is essentially made of two legs with a hinge between them, that usually has a certain resistance of friction to maintain the desired opening. From antique origins (used by the Babylonians), it is usually defined as a divider, and its aim is to copy distances. A combination compass is used to is used to trace arches and circles. Although they are essentially related to the activity of architects, engineers, topographers and navigators, they are fundamental instruments for artistic design, in which amply used as an aid in copying (see proportional compass and triangular compass).