1. having five sides and five angles

Examples

• The Pentagon building in Washington D.C. has a pentagonal shape.
• She drew a pentagonal figure on the whiteboard during geometry class.
• The ancient fortress was built with pentagonal walls for better defense.
• Each face of the soccer ball is either hexagonal or pentagonal.
• The garden was designed with pentagonal flower beds.
• The crystal had a distinctive pentagonal cross-section.