1. Plural of bipyramid; three-dimensional geometric solids formed by joining two pyramids base-to-base, commonly studied in geometry and crystallography.
Usage: Also called dipyramids; Common in mathematics, chemistry, and mineralogy

Examples

• The crystal structure exhibited several bipyramids arranged in a regular pattern.
• In geometry class, students constructed bipyramids from paper and straws.
• Hexagonal bipyramids are common forms found in certain mineral specimens.
• The mathematician explained how bipyramids relate to other polyhedra.
• Bipyramids have two apex points, one at the top and one at the bottom.