# 1911 Encyclopædia Britannica/Abscissa

**ABSCISSA**(from the Lat.

*abscissus*, cut off), in the Cartesian system of co-ordinates, the distance of a point from the axis of

*y*measured parallel to the horizontal axis (axis of

*x*). Thus PS (or OR) is the abscissa of P. The word appears for the first time in a Latin work written by Stefano degli Angeli (1623–1697), a professor of mathematics in Rome. (See Geometry, §

*Analytical*.)