What are lines that are non-coplanar called?

Lines that are non-coplanar are also known as skew lines. Lines that are skew cannot be contained in their entirety within any one particular plane.

Lines, line segments and points that are coplanar have the characteristic that they can all be contained in one common plane. Non-coplanar lines, or skew lines, do not exist in any one particular plane; no one plane can completely surround both lines at once. In addition, skew lines contain no points of intersection between the two lines. Parallel lines also do not intersect each other; however, parallel lines are coplanar because it is possible to embed them within a common plane.