Alternative form of hard-on

plural of Hard

A surname.

A surname.

Energetically engaged in or working on something; going at it.

(inorganic chemistry) The level of dissolved calcium salts in water

(mechanical engineering) The hardness of a material according to the Vickers hardness test, based on its ability to resist plastic deformation from a standard source.

plural of Vickers hardness

difficulty in hearing; partial deafness

plural of water hardness