Definitions for "Y axis"
The ordinate or the more nearly vertical axis in a graph or Cartesian coordinate system. Sometimes this numeric value is used in conjunction with the X Axis to define the location of parcels in a GIS system.
The Y axis represents the voltage displayed on the face of the oscilloscope
in a two-dimensional plot, the vertical axis. In a three-dimensional plot, the Y axis is the axis perpendicular to the X-Z plane.