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

Many proponents of hardening a school like an airport or police station have backgrounds in law enforcement or the military. Justin Pritchard, The Seattle Times, "Firms sell mass-shooting solutions, but can gadgets and hardware save lives?," 2 Oct. 2018 Over the show’s 14-and-counting seasons, patients have accidentally swallowed bombs, been skewered by trees and poles, become encased in hardening cement and much more. Jamie Ducharme, Time, "Grey's Anatomy May Be Giving You the Wrong Ideas About Medicine, Study Says," 20 Feb. 2018 Those include alternative energy production, hardening the grid against cyberattacks and weatherization programs for low-income customers. Washington Post, "Lawmakers craft bipartisan bills to end Dominion rate freeze, promise rebates," 19 Jan. 2018 In the name of fun and freedom of assembly, seven thousand cops are at this moment being deployed to harden a grid in the center of Manhattan between Thirty-Eighth Street and Central Park, and between Eighth Avenue and Sixth Avenue. Mark Warren, Popular Mechanics, "How the NYPD Secures Times Square on New Year's Eve," 23 Mar. 2017 Porcupettes are born with soft quills that start to harden and sharpen over a few days. Kelli Bender, PEOPLE.com, "This Porcupette, a.k.a. Baby Porcupine, Might Be the Cutest Zoo Birth of 2018," 11 July 2018 The most obvious next step in search of greater competitive balance would be to further harden up the cap, building on the increased luxury tax penalties and repeater taxes implemented in the most recent deal. Ben Golliver, SI.com, "Two Years After Durant’s Decision, Adam Silver Changes Tune on Superteam Warriors," 11 July 2018 Mathias said his personal goals are to hire more guidance counselors to help kids, to pay for armed police personnel in each school and then to harden the district’s schools. Lauren Ritchie, OrlandoSentinel.com, "Forget the gas tax — voters probably will be asked to tax themselves for school safety," 31 May 2018 Begin hardening off frost-tender seedlings to acclimate them to direct sun and wind. idahostatesman, "A gardening to do list for March and April | Idaho Statesman," 21 Mar. 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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Statistics for harden

Last Updated

17 Nov 2018

Look-up Popularity

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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More from Merriam-Webster on harden

Rhyming Dictionary: Words that rhyme with harden

Thesaurus: All synonyms and antonyms for harden

Spanish Central: Translation of harden

Nglish: Translation of harden for Spanish Speakers

Britannica English: Translation of harden for Arabic Speakers

Comments on harden

What made you want to look up harden? Please tell us where you read or heard it (including the quote, if possible).


to move with a clumsy heavy tread

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