- (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 quality or state of being hard, literally or figuratively.
- (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.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). hardness. Retrieved September 22, 2026, from http://smartdefine.org/hardness/definitions/2015031 |
| Chicago | Webster's. 2011. "hardness" http://smartdefine.org/hardness/definitions/2015031 (accessed September 22, 2026). |
| Harvard | Webster's 2011, hardness, Smart Define, viewed 22 September, 2026, <http://smartdefine.org/hardness/definitions/2015031>. |
| MLA | Webster's. "hardness" 27 May 2011. Web. 22 September 2026. <http://smartdefine.org/hardness/definitions/2015031> |