Hardness is a fundamental property of a material which defines its resistance to indentation which is determined by measuring its permanent depth of indentation.

Hardness is determined by the amount of indentation on the material. Smaller the indentation, harder is the stuff and vice versa.

Hardness is defined as the ability of a material to resist the permanent deformation of material through indentation, wear, scratch, abrasion, etc. It is a characteristic property which is used to measure the lasting depth of indentation