Abscissa

The horizontal coordinate (x-axis value) of a point on a graph or coordinate system, showing how far left or right the point is.

From Latin 'abscissa' (feminine past participle of 'abscindere', meaning 'to cut off'), derived from 'ab-' (from) and 'scindere' (to cut). The term was used in mathematics to describe the distance 'cut off' along the horizontal axis.