1. Lines, planes, or surfaces that intersect at right angles (90 degrees); plural of perpendicular.
Usage: Commonly used in geometry and mathematics
2. Vertical or upright structures or directions; things that stand at right angles to a horizontal surface.
Usage: General usage; architecture and construction

Examples

• The architect drew perpendiculars to ensure the walls met at exact right angles.
• In geometry class, we learned to construct perpendiculars using a compass and straightedge.
• The perpendiculars of the building's frame were perfectly aligned.
• Drop perpendiculars from the vertices of the triangle to find the altitude.
• The engineer checked that all perpendiculars were plumb before pouring the concrete.