Definition of "x-axis" []

• The horizontal axis of a two-dimensional Cartesian coordinate system. (noun)
• One of three axes in a three-dimensional Cartesian coordinate system. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Perhaps what your RP scale needs is an identity x-axis and a context y-axis?"
• "For example, the x-axis of this chart is based on “cash income.”"
• "Her deft touch rotated the Challenger ninety degrees around its y-axis, and then set the ship spinning around the x-axis as it rushed toward the swooping enemy ship."