- an instrument for the mechanical copying of plans, diagrams, etc., on any desired scale.
- a device usually consisting of two parallel, hinged, double-diamond frames, for transferring current from an overhead wire to a vehicle, as a trolley car or electric locomotive.
- an instrument consisting of pivoted levers for copying drawings, maps, etc, to any desired scale
- a sliding type of current collector, esp a diamond-shaped frame mounted on a train roof in contact with an overhead wire
- a device consisting of a parallelogram of jointed rods used to suspend a studio lamp so that its height can be adjusted
