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# .

In mathematics, abscissa (plural abscissae or abscissæ) refers to that element of an ordered pair which is plotted on the horizontal axis of a two-dimensional Cartesian coordinate system, as opposed to the ordinate. It is the first of the two terms (often labelled x and y) which define the location of a point in such a coordinate system.

$$(\overbrace{x}^\mathrm{\text{abscissa}}, \overbrace{y}^\mathrm{\text{ordinate}})$$

The usage of the word abscissa is first recorded in 1659 by Stefano degli Angeli, a mathematics professor in Rome, according to Moritz Cantor.[1] Soon thereafter, Leibniz used the term extensively in Latin in his Mathematische Schriften (1692), after which it became a standardized mathematical term. The first occurrence of the term in English is found in An Institution of Fluxions by the English mathematician Humphry Ditton (1706), where he spells the word abscisse, possibly denoting the plural.
Examples

For the point (-7, 3), -7 is called the abscissa and 3 the ordinate.

Ordinate
Function (mathematics)
Relation (mathematics)
Line chart

References

^ Earliest Known Uses of Some of the Words of Mathematics (A). Jeff Miller Web Pages. Updated November 14, 2010. Retrieved on 2011-04-24.

This article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the "relicensing" terms of the GFDL, version 1.3 or later.

Mathematics Encyclopedia