What is a "coordinate plane"?

According to the Math Planet, a coordinate plane is a two-dimensional number line that is composed of a horizontal line called the x-axis and a vertical line called the y-axis. These two lines are perpendicular with each other and intersect at a point called the origin.

Math Open Reference states that points, lines and curves can be plotted on a coordinate plane. Moreover, the two axes divide the coordinate plane into four parts called quadrants. The top right part is called the first quadrant and on the top left is the second quadrant. The third quadrant is located below the second quadrant, and the fourth quadrant is below the first quadrant.