Definition
X-coordinate
The x-coordinate is the first number in an ordered pair and gives horizontal position.
What it means
Read the first number and move sideways. A positive x-coordinate moves right from the origin; a negative one moves left. Points stacked on the same vertical line have the same x-coordinate.
Remember it
x comes first: move sideways before moving up or down.
Example
For the point (−4, 3), the first number is −4. Its x-coordinate is −4, so the point is four units to the left of the y-axis.
Watch for
A point on the y-axis has x-coordinate 0, even when its y-coordinate is not 0.
Common mix-up
The x-coordinate is the first number and shows left or right; the y-coordinate is the second and shows up or down.
Exact meaning
In an ordered pair (x, y) on a standard coordinate plane, the x-coordinate is the first coordinate. It gives horizontal position relative to the origin: positive values are to the right and negative values are to the left.