hardness
n. uncountablen. the quality of being firm and solid. You use this to describe how difficult it is to scratch, bend, or break an object.
n. the quality or condition of being rigid and resistant to pressure or deformation. In technical contexts, it refers specifically to the resistance of a material to localized plastic deformation or scratching.
The hardness of the diamond makes it perfect for cutting glass.
Engineers must test the hardness of the steel to ensure it can withstand the pressure of the bridge.
The Mohs scale provides a qualitative measure of mineral hardness by observing which substances can visibly scratch others under controlled conditions.
From Middle English hardness, hardnesse, from Old English heardnes, from heard + -nes, equivalent to hard + -ness.
Uncountable in its general sense; can be countable when referring to specific degrees or types of the quality in materials science.