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strengthen

American  
[strengk-thuhn, streng-, stren-] / ˈstrɛŋk θən, ˈstrɛŋ-, ˈstrɛn- /

verb (used with object)

  1. to make stronger; give strength to.

    Synonyms:
    support, fortify, reinforce, buttress
  2. Phonetics. to change (a speech sound) to an articulation requiring more effort, as from fricative to stop or nongeminate to geminate.


verb (used without object)

  1. to gain strength; grow stronger.

strengthen British  
/ ˈstrɛŋθən /

verb

  1. to make or become stronger

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Etymology

Origin of strengthen

First recorded in 1250–1300, strengthen is from the Middle English word strengthnen. See strength, -en 1

Explanation

To strengthen is to make something stronger! Rarr. You can strengthen your muscles by working out, or strengthen your brain by learning new words. Anytime you strengthen something, you're making it more resistant, vigorous, or tough. Taking vitamins can strengthen your immune system so you don't get sick. Lifting weights will strengthen your muscles. A powerful lock will strengthen a door. On computers, a reliable firewall will strengthen your virus protection. If something is weak, it needs to be strengthened. Congrats! You just strengthened your vocabulary by checking out this definition!

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Vocabulary lists containing strengthen

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Strengthen consumer protections by requiring every car dealer to disclose the true cost of a vehicle up front.

From MarketWatch • Feb. 13, 2026

Strengthen and enforce a “betterment policy,” to control and sometimes reject runaway requests by local governments.

From Seattle Times • Mar. 2, 2023

Strengthen national health systems based on the foundations of public health and universal health coverage and grounded in human rights and gender equality.

From Salon • Sep. 25, 2022

Strengthen current regulatory language, with increased penalty guidelines, requiring veterinarians to perform examination, diagnosis and treatment protocols and strict compliance by trainers.

From Los Angeles Times • Dec. 7, 2019

Enter, Jumala, my vessel, Enter here, O thorn most gracious,30 Strengthen thou the hero's weakness, And the weakling do thou cherish, On these far-extending waters, On the wide expanse of billows.

From Kalevala, Volume I (of 2) The Land of the Heroes by Kirby, W. F. (William Forsell)