a. [f. CO- + L. plānār-is, f. plānum PLANE.] Situated or acting in the same plane.
1862. Salmon, Geom. Three Dimensions, xiv. § 510 (1874), 442. The number of points on the line such that the line is coplanar with two of the normals at the point.
1882. Minchin, Unipl. Kinemat., 11. Coplanar concurrent forces.
