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 of hardness

• 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

Combined with the material’s monocrystalline hardness—which resists deformation and produces an ethereal, resonant tone—this construction gives Chopard’s sonneries their unmistakable symphony. —Paige Reddinger, Robb Report, 19 Nov. 2025

Li, a writer whose stories are compressed and deceptively simple, spoke with humor and a certain hardness, perhaps born of the clarity of unimaginable loss. —Literary Hub, 7 Oct. 2025

In contrast, compressive strength measures its ability to resist being squeezed or crushed, often expressed in PSI or on the Mohs hardness scale. —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

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