In a CRO (Cathode Ray Oscilloscope) measurement, a pulse delay refers to the time delay between the trigger signal and the start of the displayed waveform on the screen. This delay allows the user to synchronize the display of the waveform with a specific point in the input signal, making it easier to analyze and measure the signal accurately. By adjusting the pulse delay, the user can control when the waveform is displayed relative to the trigger signal, helping to capture and analyze specific events or signals of interest.