hardened; hardening
ˈhärd-niŋ 
ˈhär-dᵊn-iŋ
1
: to make hard or harder
2
: to confirm in disposition, feelings, or action
especially
: to make callous
hardened his heart
3
4
: to protect from blast, heat, or radiation (as by a thick barrier or placement underground)
1
: to become hard or harder
2
a
: to become firm, stable, or settled
b
: to assume an appearance of harshness or severity
her face hardened at the thought
3
: to become gradually acclimatized to unfavorable conditions
—often used with off
plants hardened off before the first frost
Examples of harden in a Sentence
The presence of certain substances in the blood can cause the arteries to harden.
These additives are designed to harden the steel.
substances that can harden the arteries
The news has hardened opposition to the government.
He had been hardened by his years of military service.
Recent Examples on the Web
It’s not hardened against attack the way some other secure browsers are.
—
PC Magazine, 11 Apr. 2025
This ultra-fine, sub-10 nanometers coherent lamellar structure slowed dislocation and stacking fault movement, stores deficits efficiently, boosts strain hardening, and prevents strain from building up in one spot.
—Georgina Jedikovska, Interesting Engineering, 10 Apr. 2025
Capital Economics cited a drop in consumer travel demand and fewer tourist visits, especially from Canada, where sentiment has hardened toward the United States because of the trade war.
—Paul Davidson, USA Today, 10 Apr. 2025
For example, the swelling in your leg might go from mild to severe, and areas of your skin might harden.
—Ruth Jessen Hickman, Md, Verywell Health, 10 Apr. 2025
See All Example Sentences for harden
Examples are automatically compiled from online sources to
show current usage.
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PC Magazine, 11 Apr. 2025
This ultra-fine, sub-10 nanometers coherent lamellar structure slowed dislocation and stacking fault movement, stores deficits efficiently, boosts strain hardening, and prevents strain from building up in one spot.
—Georgina Jedikovska, Interesting Engineering, 10 Apr. 2025
Capital Economics cited a drop in consumer travel demand and fewer tourist visits, especially from Canada, where sentiment has hardened toward the United States because of the trade war.
—Paul Davidson, USA Today, 10 Apr. 2025
For example, the swelling in your leg might go from mild to severe, and areas of your skin might harden.
—Ruth Jessen Hickman, Md, Verywell Health, 10 Apr. 2025
See All Example Sentences for harden
Cite this Entry
“Harden.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/harden. Accessed 21 Apr. 2025.
Copy CitationKids Definition
harden
verb
hard·en
ˈhärd-ᵊn
hardened; hardening
ˈhärd-niŋ
-ᵊn-iŋ
1
: to make or become hard or harder
2
: to make unfeeling or unsympathetic
hardened his heart
3
: to make or become hardy or strong
muscles hardened by exercise
4
: to protect from blast, heat, or radiation (as by a thick barrier or by placing underground)
hardened missile sites
5
a
: to become firm, stable, or settled
b
: to express harshness
hardener
noun
ˈhärd-nər
-ᵊn-ər
Biographical Definition
Harden
2 of 2biographical name (2)
Maximilian 1861–1927 originally Felix Ernst Witkowski German writer
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