1. A line or “wire” of conductive material such as copper, silver or gold, on the surface of or sandwiched inside a PCB, printed circuit board. These traces are often called individually a run. Traces carry an electronic signal or other forms of electron flow from one point to another. Traces that are on the surface of a board are covered with a non-conductive coating, except at contact or solder points, to keep unintentional contact from being made with other conductive surfaces. 2. To determine the “flow” of a program, often used as a synonym to debug.