Axes and Gridlines

The axes consist of the vertical Y axis and the horizontal X axis.

Gridlines are vertical and horizontal guidelines that appear behind a chart.

The Y axis shows the values for the data series in the chart. The X axis shows either values or categories for the data series. There is a wide range of functions for the axes including the following:

General axis settings
Time scale settings (for more information, see Making Time Scale Settings)
Gridline settings (for more information, see Displaying or Hiding Gridlines in a Chart)

The gridlines make it easier to read data from the graphic.