SOLID'ITY, noun [Latin soliditas.]

1. Firmness; hardness; density; compactness; that quality of bodies whcih resists impression and penetration; opposed to fluidity. That which hinders the apporach of two bodies moving ine towards another, I call solidity

2. Fullness of matter; opposed to hollowness.

3. Moral firmness; soundness; strength; validity; truth; certainty; as opposed to weakness or fallaciounes; as the soildity of arguments or reasonig; the solidity of principles, truths or opinious.

4. In geometry, the solid contents of a body.