The first of the two terms by which a point is referred to, in a system of fixed rectilinear coordinate (Cartesian coordinate) axes. The abscissa is also known as the "x" coordinate of a point, shown on the horizontal line, with the ordinate, also known as the "y" coordinate, shown on the vertical line
The point (3,2) has 3 as its abscissa and 2 as its ordinate.
The horizontal coordinate in a two-dimensional system of rectangular Cartesian coordinates; usually denoted by x; also, the horizontal axis of any graph
One of the elements of reference by which a point, as of a curve, is referred to a system of fixed rectilinear coordinate axes. When referred to two intersecting axes, one of them called the axis of abscissas, or of X, and the other the axis of ordinates, or of Y, the abscissa of the point is the distance cut off from the axis of X by a line drawn through it and parallel to the axis of Y. When a point in space is referred to three axes having a common intersection, the abscissa may be the distance measured parallel to either of them, from the point to the plane of the other two axes. Abscissas and ordinates taken together are called coordinates. -- OX or PY is the abscissa of the point P of the curve, OY or PX its ordinate, the intersecting lines OX and OY being the axes of abscissas and ordinates respectively, and the point O their origin