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

This tiny snail’s shell combines hardness, toughness and energy dissipation in a way that very few single-phase materials can. —Scott Travers, Forbes.com, 30 Jan. 2026

The method allows the creation of 3D objects with varying mechanical and optical properties — such as hardness and transparency — at the pixel level using a single, inexpensive material. —Mrigakshi Dixit, Interesting Engineering, 29 Jan. 2026

This included changing characteristics like the planets' sizes, the speed of their rotation, their internal heating, and the hardness of rotating fluid within their vortices. —Robert Lea, Space.com, 20 Jan. 2026

This footwear has been in style since last year and can easily make a nice contrasting outfit with having a dark leather uppers, feature rounded or squared toes that bring a contrasting hardness to mom jeans’ light washes and high-waist fit. —Aaron Royce, InStyle, 7 Jan. 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