Parallel lines are two or more lines that never intersect and have the same slope, while perpendicular lines are two lines that intersect at a right angle, and their slopes are negative reciprocals of each other.
Parallel lines are two or more lines that never intersect, while perpendicular lines are lines that intersect at a right angle, forming a 90-degree angle between them. The difference between parallel and perpendicular lines is that parallel lines never meet, whereas perpendicular lines intersect at a right angle.