[ eks-ak-sis ]
/ ˈɛksˌæk sɪs /

noun, plural x-ax·es [eks-ak-seez] /ˈɛksˌæk siz/. Mathematics.

Also called axis of abscissas. (in a plane Cartesian coordinate system) the axis, usually horizontal, along which the abscissa is measured and from which the ordinate is measured.
(in a three-dimensional Cartesian coordinate system) the axis along which values of x are measured and at which both y and z equal zero.

Origin of x-axis

First recorded in 1925–30

Can be confused

x-axis y-axis
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for x-axis

British Dictionary definitions for x-axis



a reference axis, usually horizontal, of a graph or two- or three-dimensional Cartesian coordinate system along which the x- coordinate is measured
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for x-axis


[ ĕksăk′sĭs ]

The horizontal axis of a two-dimensional Cartesian coordinate system.
One of the three axes of a three-dimensional Cartesian coordinate system.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.