On the PCB the lines which connects Pads and Via together is known as Trace .In the picture below, there are traces that electrically connect the various connectors and components to each other. A PCB trace allows signals and power to be routed between physical devices.
PCB Trace Width Calculation:
Generally PCB trace depends on parameters given below:
1-Current:How much current flows in the trace.
2-Copper Thickness:The thickness of copper or copper weight in (oz/mils/micron).
3-Temperature: How much temperature rises above when current flows.