What are parallel lines?

Parallel lines are straight lines that run in the same direction and stay exactly the same distance apart, so they never cross no matter how far they are extended. They are often marked with matching arrows.

Examples

• The two rails of a train track are parallel.
• The opposite sides of a rectangle are parallel.
• The two lines in an equals sign (=) are parallel.

Quick facts

• Parallel lines never meet, however far you draw them.
• The prefix in words like parallelogram points to its parallel sides.