Collinear points
From Latin: co- "together" , -linearis "belonging to a line,"
Definition: Points that lie on the same straight line
Try this Move any of the points around with the mouse. The others will move by themselves so they all remain collinear.

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).

Word Usage

We say that "point Q is collinear with points P, R and S". Or put another way, "the points P, Q, R and S are collinear".

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.

While you are here..

... I have a small favor to ask. Over the years we have used advertising to support the site so it can remain free for everyone. However, advertising revenue is falling and I have always hated the ads. So, would you go to Patreon and become a patron of the site? When we reach the goal I will remove all advertising from the site.

It only takes a minute and any amount would be greatly appreciated. Thank you for considering it!   – John Page

Become a patron of the site at

Other point topics