Axes is the region where the plots and graphs are drawn. Each axes has its own title, x-axis and y-axis.
On the other hand, the axis in Matplotlib refers to the scale of the graph. A two-dimensional graph has an x-axis and a y-axis, whereas a three-dimensional graph has an x-axis, a y-axis, and a z-axis.
Note: A Matplotlib figure can have one or many axes.
The following figure clearly explains the difference between axes and axis:
From the figure, you can see that this Matplotlib figure has two axes, Axes 1 and Axes 2. Both axes have their own title, X-axis, and Y-axis.
Note: Don't get confused with the grammatical meaning of axes and axis. In English grammar, axes is the plural for axis. But in Matplotlib, axes and axis are two different things.