froststar7 – https://www.hemeixinpcb.com/company/news/what-is-a-fiducial-mark-pcb-assembly.html

A circuit board is the structure of modern electronics. Whether fiducial marks call it a circuit board, pcb printed circuit card, pc board, or electronic motherboard, it serves the very same necessary function: it links and supports electronic components so they can collaborate in a controlled and reliable method. From computer systems and phones to industrial controls, medical equipment, and aerospace systems, motherboard make complex electronics useful to design, fixing, and manufacture.