Xaxes

Xaxes, or x-axes, refer to the horizontal coordinate axes in Cartesian systems. The term is commonly used in the plural when describing more than one such axis in a figure or in discussions of coordinate directions in higher-dimensional spaces.

In two dimensions, the x-axis is the horizontal line y=0 that passes through the origin; it marks values of the x-coordinate and typically increases to the right. In three dimensions, the x-axis is the line through the origin in the direction of the x-coordinate, consisting of points of the form (x, 0, 0). The x-axis is one of the principal reference lines used to locate points and to define the coordinate system.

In graphs and plots, there is usually a single x-axis, but many figures include additional x-axes to display different scales, units, or data transformations. These extra x-axes are often aligned with the primary x-axis and may be placed at the top or bottom of the plotting area, with labels reflecting their separate scales. Software for data visualization supports this arrangement through features such as dual x-axes or multiple axes, which allow overlays or synchronized ranges.

Beyond simple Cartesian plots, the concept of an x-axis extends to higher dimensions and non-Cartesian coordinate systems, where it remains the axis associated with the first coordinate in a chosen reference frame. The x-axis is a fundamental element in describing geometry and in the visualization of data.