In the graph, the x-coordinate is also known as the ordinate.

On a graph paper draw X'OX and YOY'. Here X'OX and YOY’ be the two coordinate axes. 

Then mark a point on the graph and name the point as P such that P is at the perpendicular distance of a unit from the y-axis and again similarly b units from the x-axis. Then, we denote that the coordinates of P are P(a, b)

From the above discussion, a is called the abscissa or x-coordinate of P.