n (context|geometry) 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.
(defdate|First attested in the late 17th century.)[ ]