The "x-axis" usually refers to the horizontal axis. In Excel, that would be relevant for graphs created with Excel.
Those are the four "quadrants".
It was the French mathematician Rene Descartes who created coordinated geometry using an horizontal x axis and a vertical y axis that are perpendicular to each other
Once a graph has been created, y would be the axis which is shown up and down on the graph. The x axis is shown from left to right on the graph. Both are reference lines on a graph.
Next to the axis. Next to the axis. Next to the axis. Next to the axis.
The Axis of Perdition was created in 2002.
Axis Bank was created in 1994.
Axis Mutatis was created in 1995.
The Beijing Axis was created in 2002.
Axis of Advance was created in 1998.
Blood Axis was created in 1989.
Axis - novel - was created in 2007.
Axis Communications was created in 1984.
Exploring the Axis was created in 1985.
Discordance Axis was created in 1992.
Axis Amerika was created in 1987.
Spinning on an Axis was created in 2001.