Collinear points are points that lie on the same line.
If three or more points lie on the same line, then the points are called collinear points. Let us observe the following figure, Fig (1) Fig (2) Fig (3). In Fig (1) we can see that there are infinite number of points in the given plane. Fig (2) shows the lines drawn through any two given points.  In any geometry, the set of points on a line are said to be collinear. In Euclidean geometry this relation is intuitively visualized by points lying in a row on a straight line. In geometry, collinearity is a property of a set of points, specifically, the property of lying on a single line. A set of points with this property is said to be collinear (sometimes spelled as colinear). In greater generality, the term has been used for aligned objects, that is, things being in a line or in a row It's a similar idea to coplanar. Just as collinear points all lie on a straight line, in the three dimensional world, when a set of points all lie on the same plane, they are called coplanar. For more see Coplanar points. Obviously two points are always collinear, since a straight line can always be drawn through two points. Sometimes it is spelled 'colinear' (with one L). Three points, , and in trilinear coordinates are collinear if the determinant. (9). (Kimberling 1998, p. 29). Let points, , and lie, one each, on the sides of a triangle or their extensions, and reflect these points about the midpoints of the triangle sides to obtain, , and. A line on which points lie, especially if it is related to a geometric figure such as a triangle, is sometimes called an axis. Two points are trivially collinear since two points determine a line. Three points for, 2, 3 are collinear iff the ratios of distances satisfy. (1). A slightly more tractable condition is obtained by noting that the area of a triangle determined by three points will be zero iff they are collinear (including the degenerate cases of two or all three points being concurrent), i.e., (2) Definition of Collinear Points. Collinear points are points that lie on the same line. The word 'collinear' breaks down into the prefix 'co-' and the word 'linear'. 'Co-' indicates togetherness, as in 'coworker' or 'cooperate'. 'Linear' refers to a line. So, collinear basically means points that hang out on the same line together.  Best Answer: points are colinear if they belong to the same line non-colinear, means that they do not belong to the same line coplanar, is that points belong to the same plane non-coplanar is that they do not belong to the same plane. Source(s): h. locuaz · 9 years ago. Thumbs up. Collinear :The vectors are in the same line. Non Collinear :The vectors are not in the same line. Coplanar :The vectors are in the same plane. Non coplanar :The vectors are not In telecommunications, a collinear antenna array is an array of dipole antennas mounted in such a manner that the corresponding elements of each antenna are parallel and collinear, that is they are located along a common line or axis. 
http://www.mathcaptain.com/geometry/collinear-points.html https://en.wikipedia.org/wiki/Collinearity http://www.mathopenref.com/collinear.html http://mathworld.wolfram.com/Collinear.html http://study.com/academy/lesson/collinear-points-in-geometry-definition-examples.html https://in.answers.yahoo.com/question/index?qid=20061003205708AADrwNX https://en.wikipedia.org/wiki/Collinear_antenna_array
what is collinear