1. 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.
That which hinders the approach of two bodies when they are moving one toward another, I call solidity. --Locke.
2. 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. Geom. The solid contents of a body; volume; amount of inclosed space.
Syn: -- Firmness; solidness; hardness; density; compactness; strength; soundness; validity; certainty.
n 1: the consistency of a solid [syn: solidness] [ant: porosity]
2: state of having the interior filled with matter [ant: hollowness]