Hardness

Definitions

1. The quality of being hard.
   countable, uncountable
2. An instance of this quality; hardship.
   countable, uncountable
3. The quantity of calcium carbonate dissolved in water, usually expressed in parts per million (ppm).
   countable, uncountable
4. The resistance to scratching, cutting, indentation or abrasion of a metal or other solid material.
   countable, uncountable
5. The penetrating ability of electromagnetic radiation, such as x-rays; generally, the shorter the wavelength, the harder and more penetrating the radiation.
   countable, uncountable
6. The measure of resistance to damage of a facility, equipment, installation, or telecommunications infrastructure when subjected to attack.
   countable, uncountable
7. A measure of how hard a material is.
   countable

Equivalents

Examples

“Who can number⟳ the cloudes in wiſedom? or who can ſtay the bottles of heauen, / When the duſt groweeh^([sic – meaning groweth]) into hardneſſe and the clods cleaue faſt together?”

“The hardness of the material was high.”

““This material has a specific hardness and is chemically very stable. It forms naturally from calcium alone, but bacteria accelerate the transformation into calcium carbonate,” explains Alejandro Montesinos, head of the Decarbonization, Climate Change⟳, and Circular Economy Research⟳ Group at Tec de Monterrey and a member of the Institute of Advanced Materials and Sustainable Manufacturing.”

CEFR level