Abscissa and ordinate

In mathematics, the abscissa (/æbˈsɪs.ə/; plural abscissae or abscissas) and the ordinate are respectively the first and second coordinate of a point in a Cartesian coordinate system:

abscissa ${\displaystyle \equiv x}$-axis (horizontal) coordinate

ordinate ${\displaystyle \equiv y}$-axis (vertical) coordinate

Together they form an ordered pair which defines the location of a point in two-dimensional rectangular space.

More technically, the abscissa of a point is the signed measure of its projection on the primary axis. Its absolute value is the distance between the projection and the origin of the axis, and its sign is given by the location on the projection relative to the origin (before: negative; after: positive). Similarly, the ordinate of a point is the signed measure of its projection on the secondary axis. In three dimensions, the third direction is sometimes referred to as the applicate.