1. A marker that is included in an image in order to provide accurate positional or measurement information. This may be a physical object that is placed in the scene being photographed. Alternatively, cameras used for surveying often modify the optics to superimpose thin cross-like fiducial markings on the image to assist in precise measurement.

2. A marker put on a printed circuit board to make it easier for automated equipment that attaches components to find the precise location for each. This is very important for ball grid array devices that require very precise alignment.