1. the quality or state of being solid; firmness or hardness
2. reliability, dependability, or soundness
3. the quality of being substantial or having substance

Examples

• The solidity of the concrete foundation ensured the building’s stability.
• We tested the solidity of the ice before walking across the frozen lake.
• The company’s financial solidity made it an attractive investment.
• His reputation for solidity and honesty earned him widespread respect.
• The solidity of her argument convinced even the skeptics.
• The wooden table’s solidity impressed the furniture buyer.
• The bridge’s solidity was questioned after the earthquake.