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

Side effects can include rash, pain, swelling, or hardness at the site of injection. —Anna Halkidis, Parents, 4 July 2025

This action served to strengthen those walls, thus increasing the stiffness and hardness of the wood by 260.5% and 127%, respectively. —Ben Coxworth, New Atlas, 29 Apr. 2025

There’s still no shortage of old-school discipline and hardness about Wade. —D. Watkins, The Atlantic, 10 Apr. 2025

The dye formula may be same, but there are differences in water hardness and minerals. —Angela Velasquez, Sourcing Journal, 30 July 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