Any set of two or more points that lie on the same line are said to be collinear.

In this illustration, $A,$ $B,$ and $C$ are all considered to be collinear. In contrast, $D$ does not lie on the same line as the other points.

However, since any two points can be used to define a line, $D$ is still considered to be collinear with the other points individually. Therefore, there are four sets of collinear points on the graph.