AxesLabel is an option for graphics functions that specifies labels for axes.
AxesLabel -> None specifies that no labels should be given.
AxesLabel -> label specifies a label for the axis of a two-dimensional plot, and the axis of a three-dimensional plot.
AxesLabel -> xlabel, ylabel, ... specifies labels for different axes.
By default, axes labels in two-dimensional graphics are placed at the ends of the axes. In three-dimensional graphics, they are aligned with the middles of the axes.
Any expression can be specified as a label. It will be given in OutputForm. Arbitrary strings of text can be given as "text".
See The Mathematica Book: Section 1.9.3, Section 1.9.7, Section 2.9.5 and Section 2.9.13.
See also: PlotLabel, FrameLabel.