Definitions from Wiktionary (hardness)

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

---

▸ Words similar to hardness
▸ Usage examples for hardness

▸ Idioms related to hardness
▸ Wikipedia articles (New!)
▸ Popular adjectives describing hardness
▸ Words that often appear near hardness
▸ Rhymes of hardness

▸ Invented words related to hardness