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

Finally, impact strength assesses a material’s ability to absorb sudden shocks without shattering, highlighting that the hardness alone doesn’t always mean toughness. —Atharva Gosavi, Interesting Engineering, 26 Sep. 2025

Minerals like calcium and magnesium can cling to the surface over time, especially in areas with high water hardness. —Daley Quinn, Southern Living, 23 Sep. 2025

Despite his small stature, there is a mental hardness and tenacity to his game. —Steve Conroy, Boston Herald, 19 Sep. 2025

The water’s mineral content and its softness or hardness comes into play with the fermenting process, Martin said. —Maggie Menderski, Louisville Courier Journal, 4 Sep. 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