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

Experts recommend descaling every one to three months, depending on water hardness, and suggest preventative measures like occasional hot cycles, using the correct detergent amount, and regular wiping of machine parts. —Madeline Buiano, Martha Stewart, 14 Mar. 2026

The Liquefy choice offers a dedicated interface with control over brush size, hardness, opacity, ramp type (Gaussian, Linear, and several more), and speed. —Michael Muchmore, PC Magazine, 13 Mar. 2026

One involved the radiation hardness of silicon sensors at cryogenic temperatures, referred to in physics as the Lazarus effect. —Liz Wegerer, IEEE Spectrum, 24 Feb. 2026

Diamond grit is used by industrial manufacturers — including in the semiconductor, automotive and energy sectors — for its hardness properties. —Dallas Morning News, 18 Feb. 2026

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