Parallel lines are lines in the same plane that never intersect, regardless of how far they are extended. Skew lines, on the other hand, are lines that do not lie in the same plane, meaning they do not intersect and are not parallel. Skew lines are oblique to each other, meaning they are neither parallel nor perpendicular. In simple terms, parallel lines never intersect and are in the same plane, while skew lines never intersect and are in different planes.
