hardness

n. strength, toughness; stiffness; firmness, solidness

Hardness refers to various properties of matter in the solid phase that give it high resistance to various kinds of shape change when force is applied. Hard matter is contrasted with soft matter.Macroscopic hardness is generally characterized by strong intermolecular bonds. However, the behavior of solid materials under force is complex, resulting in several different scientific definitions of what might be called "hardness" in everyday usage.In materials science, there are three principal operational definitions of hardness:Scratch hardness: Resistance to fracture or plastic (permanent) deformation due to friction from a sharp objectIndentation hardness: Resistance to plastic (permanent) deformation due to impact from a sharp objectRebound hardness: Height of the bounce of an object dropped on the material, related to elasticity.
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Noun
1. the property of being rigid and resistant to pressure; not easily scratched; measured on Mohs scale
(antonym) softness
(hypernym) consistency, consistence, body
(hyponym) firmness
(attribute) hard
2. devoid of passion or feeling
(synonym) unfeelingness, callousness, insensibility
(hypernym) insensitivity, insensitiveness
3. the quality of being difficult to do; "he assigned a series of problems of increasing hardness"
(hypernym) difficulty, difficultness
4. excessive sternness; "severity of character"; "the harshness of his punishment was inhuman"; "the rigors of boot camp"
(synonym) severity, harshness, rigor, rigour, inclemency, stiffness
(hypernym) sternness, strictness

(n.)
The quality or state of being hard, literally or figuratively.
  

(n.)
The peculiar quality exhibited by water which has mineral salts dissolved in it. Such water forms an insoluble compound with soap, and is hence unfit for washing purposes.
  

(n.)
The cohesion of the particles on the surface of a body, determined by its capacity to scratch another, or be itself scratched;-measured among minerals on a scale of which diamond and talc form the extremes.
  

The quality of metal that describes resistance to denting, scratching, or bending.