1.  solidness(n = noun.state) solid, solid state - the state in which a substance has no tendency to flow under moderate stress; resists forces (such as compression) that tend to deform it; and retains a definite size and shape;
is a kind of state, state of matter
Derived form adjective solid₂

2.  solidness(n = noun.attribute) solidity - the consistency of a solid;
is a kind of body, consistence, consistency, eubstance
has particulars: compactness, impermeability, impermeableness
Derived forms adjective solid₈, adjective solid₃

3.  solidness(n = noun.attribute) substantiality, substantialness - the quality of being substantial or having substance;
is a kind of corporality, corporeality, materiality, physicalness
Derived forms adjective solid₄, adjective solid₇

4.  solidness(n = noun.attribute) solidity - the quality of being solid and reliable financially or factually or morally; "the solidity of the evidence worked in his favor"; "the solidness of her faith gave her enduring hope"
is a kind of dependability, dependableness, reliability, reliableness
Derived forms adjective solid₁, adjective solid₁₃, adjective solid₁₂, adjective solid₁₁

1.  State or quality of being solid; firmness; compactness; solidity, as of material bodies. [1913 Webster]

2.  Soundness; strength; truth; validity, as of arguments, reasons, principles, and the like. [1913 Webster]

N  density, solidity, solidness, impenetrability, impermeability, incompressibility, imporosity, cohesion, constipation, consistence, spissitude, specific gravity, hydrometer, areometer, condensation, caseation, solidation, solidification, consolidation, concretion, coagulation, petrification, crystallization, precipitation, deposit, precipitate, inspissation, gelation, thickening, indivisibility, indiscerptibility, insolubility, indissolvableness, solid body, mass, block, knot, lump, concretion, concrete, conglomerate, cake, clot, stone, curd, coagulum, bone, gristle, cartilage, casein, crassamentum, legumin, superdense matter, condensed states of matter, dwarf star, neutron star, dense, solid, solidified, caseous, pukka, coherent, cohesive, compact, close, serried, thickset, substantial, massive, lumpish, impenetrable, impermeable, nonporous, imporous, incompressible, constipated, concrete, knotted, knotty, gnarled, crystalline, crystallizable, thick, grumous, stuffy, undissolved, unmelted, unliquefied, unthawed, indivisible, indiscerptible, infrangible, indissolvable, indissoluble, insoluble, infusible.