Signal integrity is the ability of a signal to generate correct responses in a circuit. A signal with good signal integrity has digital levels at required voltage levels at required times.

A portion of the signal power (voltage and current) transmitted down the line goes into the load, and a portion is reflected back

The quantity that measures the opposition of a circuit to the passage of a current and therefore determines the amplitude of the current.

Skew Signal is the difference in time in arrival of one signal to different receivers on the same net.