The hardness of a metal or part, as represented by the number obtained from the ratio between the load applied on the spherical area of the impression made by a steel ball forced into the surface of the material tested. Found on https://steelforge.com/literature/steelog-the-5000-word-metals-glossary/
The value of hardness of a metal on an arbitrary scale representing kg/mm², determined by measuring the diameter of the impression made by a ball of given diameter applied under a known load. Values are expressed in Brinell Hardness Numbers, BHN. Found on https://www.metaltek.com/resources/glossary/