- Skew lines are straight lines in a three dimensional form which are not parallel and do not cross.
An example of skew lines are the sidewalk in front of a house and a line running across the top edge of a side of a house.
Lines ab and cd are skew lines.
Math. two or more lines that lie in different planes, are not parallel, and do not intersect
Straight lines that are not in the same plane and do not intersect.