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
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
The ego, the hardness, the … callousness of anything that might be on the heart or the mind had literally just melted away.
—
Kelsie Hoffman, CBS News, 5 Jan. 2026
For context, Limestone, which also contains calcite, has a 2 or 3 hardness rating.
—Barbara Bellesi Zito, Southern Living, 2 Jan. 2026
The hardness of the food and the strength of the beak also influence what a bird eats.
—Randy McMullen, Mercury News, 22 Dec. 2025
And also this kind of hardness that comes with being disappointed by life and disappointed by one turn of events after another.
—Vogue, 2 Dec. 2025
See All Example Sentences for hardness
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Kelsie Hoffman, CBS News, 5 Jan. 2026
For context, Limestone, which also contains calcite, has a 2 or 3 hardness rating.
—Barbara Bellesi Zito, Southern Living, 2 Jan. 2026
The hardness of the food and the strength of the beak also influence what a bird eats.
—Randy McMullen, Mercury News, 22 Dec. 2025
And also this kind of hardness that comes with being disappointed by life and disappointed by one turn of events after another.
—Vogue, 2 Dec. 2025
See All Example Sentences for hardness
Cite this Entry
“Hardness.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/hardness. Accessed 6 Jan. 2026.
Copy CitationKids 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
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