1. the quality or state of being closely and firmly packed together
2. the quality of being small in size but containing much

Examples

• The compactness of the soil made it difficult for water to penetrate.
• She appreciated the compactness of her new apartment in the city.
• The compactness of the design allowed more features in less space.
• The snow’s compactness made it perfect for building snowmen.
• Urban planners praised the compactness of the new development.
• The compactness of the book made it easy to carry while traveling.