hardness

== English == === Alternative forms === hardnesse (obsolete) === Etymology === From Middle English hardness, hardnesse, from Old English heardnes, from heard + -nes. Equivalent to hard +‎ -ness. === Pronunciation === (General American) enPR: härdʹnəs, IPA(key): /ˈhɑɹdnəs/ (Received Pronunciation) IPA(key): /ˈhɑːdnəs/ Hyphenation: hard‧ness === Noun === hardness (countable and uncountable, plural hardnesses) The quality of being hard. An instance of this quality; hardship. (inorganic chemistry) The quantity of calcium carbonate dissolved in water, usually expressed in parts per million (ppm). The resistance to scratching, cutting, indentation or abrasion of a metal or other solid material. (physics) The penetrating ability of electromagnetic radiation, such as x-rays; generally, the shorter the wavelength, the harder and more penetrating the radiation. The measure of resistance to damage of a facility, equipment, installation, or telecommunications infrastructure when subjected to attack. (countable, engineering) A measure of how hard a material is ==== Derived terms ==== ==== Translations ==== === See also === hardiness === References === “hardness”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC. === Anagrams === Dashners