strengthen
Americanverb (used with object)
verb (used without object)
verb
Other Word Forms
Derived Forms
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overstrengthenverb
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prestrengthenverb (used with object)
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unstrengtheningadjective
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strengtheninglyadverb
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strengthenernoun
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restrengthenverb
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unstrengthenedadjective
Conjugated Forms
Present
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has strengthenedperfect 3rd person singular
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have strengthenedperfect
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has been strengtheningperfect progressive 3rd person singular
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is strengtheningprogressive 3rd person singular
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are strengtheningprogressive
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am strengtheningprogressive 1st person singular
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strengtheningparticiple
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strengthenssingular 3rd person
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have been strengtheningperfect progressive
Past
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had strengthenedperfect
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was strengtheningprogressive singular
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were strengtheningprogressive plural
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had been strengtheningperfect progressive
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strengthenedsimple
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strengthenedparticiple
Future
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!
Vocabulary lists containing strengthen
President Obama's second inaugural address
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Spelling Practice, Unit 2
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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.
The signed order directs federal agencies to strengthen defenses against advanced AI systems and creates a voluntary framework for labs to share frontier models with the government before public release.
From The Wall Street Journal • Jun. 9, 2026
“We are working to identify the cause and strengthen safeguards to prevent this from happening again.”
From Los Angeles Times • Jun. 9, 2026
Chief Executive Carlo Messina called it a "risk-free" move during a conference call with journalists, saying it "will strengthen our leading position in Italy, particularly in its wealthiest regions" such as Lombardy and Tuscany.
From Barron's • Jun. 8, 2026
Such flexibility could improve coverage, strengthen reliability, and increase operational efficiency.
From Science Daily • Jun. 6, 2026
I will work hard to improve my mind and strengthen my body.
From "All American Boys" by Jason Reynolds
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
