Blank PCB is a printed circuit board, also called printed wiring board, which is an important electronic component, the support of the electron component, and the supplier of the electrical connection for the electron component. Since it is made with electron printing, it is called a "printed" circuit board.
As the electronic instruments become more and more complicated, the parts they need become much more accordingly, and the circuit and the parts on the board become denser. The blank PCB (without parts on) is often called the "Printed Wiring Board (PWB)". The substrate of the board is made of materials with attribution of insulation, thermal insulation, and inflexibility. The tiny wires can be seen on the surface is the copper foil which had been covered the whole board, but partially etched, then the remaining part formed the tiny netted wires. And these wires are called conductor pattern or electric wiring, which is used for offering the electrical connection for parts on PCB.
Generally, the color of the PCB is green or brown, which is the color of the solder mask. It is the protective layer of insulation to protect the copper foil and preventing the parts from being soldered onto the incorrect positions. Silkscreen will be printed on the solder mask where words and marks (mostly white) will be printed in order to highlight each position of the parts. The silkscreen is also called a legend.