# Abscissa Definition

In mathematics, the abscissa and the ordinate are respectively the first and second coordinates of a point in a coordinate system. The abscissa is the first coordinate in an ordered pair and the ordinate is the second coordinate. For instance with the point (3, 2) the abscissa is 3 and the ordinate is 2.

## Overview

The abscissa of a point is the signed measure of its projection on the primary axis, whose absolute value is the distance between the projection and the origin of the axis, and whose sign is given by the location on the projection relative to the origin (before: negative; after: positive).

The ordinate of a point is the signed measure of its projection on the secondary axis, whose absolute value is the distance between the projection and the origin of the axis, and whose sign is given by the location on the projection relative to the origin (before: negative; after: positive).

Usually these are the horizontal and vertical coordinates of a point in a two-dimensional rectangular Cartesian coordinate system. The terms can also refer to the horizontal and vertical axes respectively (typically x-axis and y–axis) of a two-dimensional graph. An ordered pair consists of two terms: the abscissa (horizontal, usually x) and the ordinate (vertical, usually y) which define the location of a point in two-dimensional rectangular space.

### Related Definitions

### Sources

“Abscissa and Ordinate.” Wikipedia, Wikimedia Foundation, 6 Feb. 2020, en.wikipedia.org/wiki/Abscissa_and_ordinate.