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

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

The severity of water spots varies depending on your local water hardness. —Nafeesah Allen, Better Homes & Gardens, 2 June 2025

The hardness of seats, even those that recline flat into a bed, is a common pain point for many customers on long-haul flights. —Eileen Falkenberg-Hull, MSNBC Newsweek, 20 May 2025

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