# Abscissas

(Science: geometry) One of the elements of reference by which a point, as of a curve, is referred to a system of fixed rectilineal 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.

Origin: L, fem. Of abscissus, p. P. Of absindere to cut of. See Abscind.