hardness

noun

hard·​ness ˈhärd-nəs 

1

: the quality or state of being hard

2

a

: the cohesion of the particles on the surface of a mineral as determined by its capacity to scratch another or be itself scratched compare mohs' scale

b

: resistance of metal to indentation under a static load or to scratching

Synonyms

• hardship
• difficulty

Examples of hardness in a Sentence

the hardness of a diamond

The wood's hardness makes it suitable for carving.

Recent Examples on the Web

Minerals like calcium and magnesium can cling to the surface over time, especially in areas with high water hardness. —Daley Quinn, Southern Living, 1 July 2025

Generally speaking, high-quality Western knives have 59-62 HRC, a measurement of the hardness of materials, whereas Japanese knives’ HRC ranges from 60 to 65. —Akiko Katayama, Forbes.com, 13 June 2025

The hardness enables the blades to be sharpened at a much steeper angle than Western knives. —Akiko Katayama, Forbes.com, 13 June 2025

Barnaby is working with a team on improving radiation hardness in FinFETs. —IEEE Spectrum, 15 Oct. 2024

Word History

First Known Use

before the 12th century, in the meaning defined at sense 1

Phrases Containing hardness

• Brinell hardness
• Brinell hardness number

Rhymes for hardness

• microhardness

Kids Definition

hardness

noun

hard·​ness ˈhärd-nəs 

1

: the quality or state of being hard

2

: the ability of a substance (as a mineral) to scratch another substance or be itself scratched