hard·en | \ˈhär-dᵊn \
hardened; hardening\ˈhärd-niŋ, ˈhär-dᵊn-iŋ \

Definition of harden 

(Entry 1 of 3)

transitive verb

1 : to make hard or harder

2 : to confirm in disposition, feelings, or action especially : to make callous hardened his heart

3a : inure, toughen harden troops

b : to inure to unfavorable environmental conditions (such as cold) often used with off harden off seedlings before transplanting

4 : to protect from blast, heat, or radiation (as by a thick barrier or placement underground)

intransitive verb

1 : to become hard or harder

2a : 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


biographical name (1)
Har·den | \ˈhär-dᵊn \

Definition of Harden (Entry 2 of 3)

Sir Arthur 1865–1940 English chemist


biographical name (2)

Definition of Harden (Entry 3 of 3)

Maximilian 1861–1927 originally Felix Ernst Witkowski German writer

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Synonyms & Antonyms for harden

Synonyms: Verb

fortify, indurate, inure, season, steel, strengthen, toughen

Antonyms: Verb


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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.
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Recent Examples on the Web: Verb

But the argument does align with a common contemporary view that partisan identification has hardened to the point where most political battles come down to who can best turn out their base. Gilbert Garcia, San Antonio Express-News, "O’Rourke’s hopes hinge on persuasion as well as turnout," 7 July 2018 According to the car manufacturer, the diaphragm material in the fuel pulsation dampers of certain engines can harden over time and crack, allowing fuel to leak and creating a risk of fire. Renae Reints, Fortune, "Lexus Recalls 121,000 Cars Due to Risk of Fuel Leaks," 27 June 2018 And once it’s shaped and hardened, the rest is just arithmetic and money. John Kass, chicagotribune.com, "For Mayor Globe-trotter, it's the money that matters," 13 July 2018 Toyota says a diaphragm material in the fuel injection system can harden over time and crack, allowing fuel to leak. BostonGlobe.com, "Boston Children’s named best pediatric hospital in the country for fifth year," 27 June 2018 Moms Demand Action will continue to focus its efforts, Sprunger said, on strengthening gun laws, rather than hardening school buildings. Arika Herron, Indianapolis Star, "We don’t know how safe Indiana schools are. Here’s why.," 10 June 2018 The conventional wisdom is that the outlandish fiscal plans of the populist government that took office last week will further harden German hearts against proposals to spread risk in the euro area. The Economist, "France's plans for euro-zone reform get a lukewarm German response," 9 June 2018 In retrospect, the story served to soften the ground for what was to follow but harden the opinions already in concrete. Ron Richmond For The Oregonian/oregonlive, OregonLive.com, "Inside Luke Heimlich's senior season with the Oregon State baseball team," 8 June 2018 Or how about when Prince Harry raised his bride-to-be's veil, and for one brief moment, even the most hardened of cynics swooned a little inside? Aj Willingham, CNN, "Every romantic, emotional moment from one heck of a royal wedding," 19 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'harden.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of harden


13th century, in the meaning defined at transitive sense 1

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Phrases Related to harden

harden one's heart

Statistics for harden

Last Updated

6 Oct 2018

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Time Traveler for harden

The first known use of harden was in the 13th century

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More Definitions for harden



English Language Learners Definition of harden

: to become hard or firm or to make (something) hard or firm

: to become more definite and strongly felt or to make (something) more definite and strongly felt

: to make (someone) hard : to make (someone) less emotional and less likely to feel sorry for other people


hard·en | \ˈhär-dᵊn \
hardened; hardening

Kids Definition of harden

1 : to make or become hard or harder By now the cement has hardened.

2 : to make or become hardy or strong Years of tough work had hardened his muscles.

3 : to make or become stubborn or unfeeling She hardened her heart and refused to forgive him.

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Comments on harden

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