The quality of being difficult or unpleasant to experience.
The quality of being harsh or severe in the way one speaks or behaves toward people.
An area that protrudes from a surface.
A section of a fault line with high friction, such that there is no movement along this part of the fault except during an earthquake.
The quality of having a rough or uneven surface.
Something that is harsh and difficult to endure.
An instance of this quality; hardship.
The quality of being hard.
The resistance to scratching, cutting, indentation or abrasion of a metal or other solid material.
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.
A measure of how hard a material is
The quantity of calcium carbonate dissolved in water, usually expressed in parts per million (ppm).