|n.||1.||(Geom.) One of the elements of reference by which a point, as of a curve, is referred to a system of fixed rectilineal coördinate axes.|
|Noun||1.||abscissa - the value of a coordinate on the horizontal axis|
|(mathematics)||abscissa - The x coordinate on an (x, y) graph; the input of
a function against which the output is plotted.|
y is the "ordinate".
See Cartesian coordinates.