It’s known as the scale break which is a stripe drawn across the plotting area of a chart to denote a break in continuity between the high and low values on a value axis (usually the vertical axis). We can use a scale break to display two distinct ranges
in the same chart area.
To enable the scale break on a chart, we can use the following steps:
Right-click the vertical axis and then click Axis Properties. The Vertical Axis Properties dialog box opens.