SOLIDITY

noun the solid contents of a body; volume; amount of inclosed space.

2. solidity ·noun moral firmness; soundness; strength; validity; truth; certainty;

— as opposed to weakness or fallaciousness; as, the solidity of arguments or reasoning; the solidity of principles, triuths, or opinions.

3. solidity ·noun the state or quality of being solid; density; consistency, — opposed to fluidity; compactness; fullness of matter, — opposed to openness or hollowness; strength; soundness, — opposed to weakness or instability; the primary quality or affection of matter by which its particles exclude or resist all others; hardness; massiveness.