A phase displacement of two alternating quantities with the same frequency occurs if they reach their maximum and zero values at different times. Phase displacement is indicated by the angle $\varphi [..]

The extent to which voltage and current waveforms are out of synchronous phase with one another. Current lags or leads voltage, depending on whether the current waveform crosses a reference point after or before the voltage waveform, respectively. Phase displacement can be expressed as a unit of time, as a fraction of the period, or as an angle in [..]

the difference in phase between the alternating electrical current or wave forms