hard·​en | \ ˈhär-dᵊn How to pronounce harden (audio) \
hardened; hardening\ ˈhärd-​niŋ How to pronounce hardening (audio) , 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 offharden 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 offplants hardened off before the first frost


biographical name (1)
Har·​den | \ ˈhär-dᵊn How to pronounce Harden (audio) \

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

Antonyms: Verb

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Examples of harden in a Sentence

Verb 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 Coach Austin Parkinson knew the tough start to the season would harden his squad, but a loss to Youngstown State in the conference opener forced him to have a heart-to-heart with his players. Akeem Glaspie, Indianapolis Star, "13-game win streak over, IUPUI women eyeing league title and more," 20 Feb. 2020 The cold weather hardened the rings, hot gas escaped from one and hit the main fuel tank, causing a hole and fuel explosion. Lee Roop | Lroop@al.com, al, "Federal court rejects NASA manager’s Challenger movie lawsuit," 13 Feb. 2020 In those rare cases—when there’s just hardened, blackened, caked-on stuff—Dahmen will reach for a rotary tool with an abrasive buffer before swapping the attachment for one with softer nylon bristles. Katherine Martinelli, Popular Science, "The key to cleaning copper cookware is probably in your fridge," 24 Jan. 2020 As the concrete began to settle and harden, the four workers from the seventh floor were pulled out and taken to local hospitals. Sharon Coolidge, Cincinnati.com, "'We will do whatever we can': Inside the search for the man buried in building collapse," 27 Nov. 2019 The harvest of its lax work in hardening its infrastructure against fire-prone vegetation during windy periods was the catastrophic fires of 2017 and 2018, the liability for which pushed the company to file for bankruptcy this year. Michael Hiltzik, Los Angeles Times, "Column: The hedge fund battle to control PG&E leaves us no one to root for," 17 Oct. 2019 Some of that money was spent sensibly, for example on hardening power stations and hospitals. The Economist, "Climate change is a remorseless threat to the world’s coasts," 17 Aug. 2019 But despite hardening attitudes, the refugees are putting down roots, especially in border towns like Reyhanli, picking up Turkish habits and spreading their own. The Economist, "The new Turks Syrians are putting down roots in Turkey," 6 Feb. 2020 Such suspicions only hardened after the American killing of Maj. Vivian Yee, New York Times, "For Lebanon’s Shiites, a Dilemma: Stay Loyal to Hezbollah or Keep Protesting?," 4 Feb. 2020

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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Time Traveler for harden

Time Traveler

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

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Statistics for harden

Last Updated

24 Feb 2020

Cite this Entry

“Harden.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/harden. Accessed 26 Feb. 2020.

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More Definitions for harden


How to pronounce Harden (audio)

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 How to pronounce harden (audio) \
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

Thesaurus: All synonyms and antonyms for harden

Rhyming Dictionary: Words that rhyme with harden

Spanish Central: Translation of harden

Nglish: Translation of harden for Spanish Speakers

Britannica English: Translation of harden for Arabic Speakers

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