circuit board - “A single rigid board of insulating material on which an electric circuit has been built. It often has an * edge connector at one end for making all the connections to other circuits so that the board may be plugged into a piece of equipment. Circuit boards come in a variety of sizes, some of which are standardized. The term circuit card is often used synonymously but is sometimes considered smaller than a circuit board. See also backplane, printed circuit, PCB - printed circuit board.” (Fair Use ODCS)