what is a vertical axis
y-axâ¢is. 1. (in a plane Cartesian coordinate system) the axis, usu. vertical, along which the ordinate is measured and from which the abscissa is measured. 2. (in a three-dimensional Cartesian coordinate system) the axis along which values of y are measured and at which both x and z equal zero.. 1. (Mathematics) a reference axis, usually vertical, of a graph or two-or three-dimensional Cartesian coordinate system along which the y-coordinate is measured. (ËwaÉªËaek ËwaÉªËÃ¦k). sÉªs., n. pl-yâ¢ax (es ËwaÉªËaek). ËwaÉªËÃ¦k siz