Non-collinear points are any group of three or more points that do not fall on the same straight line. More than two points in the group are needed for non-collinear points, since any two points can form a straight line.
To test if points are non-collinear, attempt to draw a line through all the points. If the line must curve to cross through one or more of the points, then the group of points is non-collinear.
The opposite of non-collinear is collinear, which means that the points in a group can form a straight line. Groups of two points are automatically collinear.