Synonyms

strengthen

American

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

verb (used with object)

to make stronger; give strength to.

Synonyms:

support, fortify, reinforce, buttress
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)

to gain strength; grow stronger.

strengthen British

/ ˈstrɛŋθən /

verb

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

Derived Forms

Inflected Forms

Participles

Conjugated Forms

Present

Past

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!

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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.

See Examples For:

strengthen strengthens strengthened strengthening

Airbnb is being “very selective” about adding hotel inventory, making sure that the chosen offerings strengthen the platform rather than compete with home listings, Mertz said.

From MarketWatch ● Aug. 11, 2026

They could strengthen control over the transistor gate, or they could protect the mobility of the charge carriers moving through the device.

From Science Daily ● Aug. 9, 2026

Pakistan's foreign ministry said Friday the pact meant an attack on any member would be regarded as an attack on all, adding it was "intended to strengthen collective deterrence".

From Barron's ● Aug. 8, 2026

Winds are likely to strengthen at times as well.

From BBC ● Aug. 7, 2026

“Good work, mice, strengthen my gates. I wouldn’t want to rule a fortress with broken doors.”

From "Redwall" by Brian Jacques

“We believe it strengthens their ability to fight in a high intensity, communications-limited environment,” he said.

From The Wall Street Journal ● Aug. 5, 2026

The researchers say they still do not know exactly how APOE2 stabilizes the nuclear envelope and strengthens DNA repair.

From Science Daily ● Jul. 24, 2026

“The deal strengthens AMD’s strategic partnership, competitive positioning, and long-term revenue opportunities,” Hendi Susanto, a portfolio manager at Gabelli Funds, said in emailed comments regarding Anthropic.

From MarketWatch ● Jul. 22, 2026

"There is an ecosystem that's conducive to the emergence of entrepreneurs like us. That strengthens our confidence in the outlook," said Yattabare, who now hopes to conquer the European market.

From Barron's ● Jul. 20, 2026

Appealing to authority—whether by quoting a commonplace or the words of a named source— always strengthens an argument.

From "Words Like Loaded Pistols" by Sam Leith

This summer, Slegers has strengthened her hand with seven new players, including full-back Ona Batlle, Caldentey's compatriot, and England dynamo Georgia Stanway to stiffen midfield.

From BBC ● Aug. 7, 2026

Seoul has strengthened surveillance and maintained readiness for possible additional launches while sharing information with its security allies the United States and Japan, the JCS said.

From Barron's ● Aug. 6, 2026

Federal oversight expanded further with the Deficit Reduction Act of 2005, which created the Medicaid Integrity Program and strengthened federal oversight of state programs.

From Salon ● Aug. 5, 2026

As a consequence of the intervention, the Japanese currency strengthened almost 5% from last week’s forty-year low of ¥164 to ¥156.70 on Monday.

From MarketWatch ● Aug. 3, 2026

“He said that if I strengthened my control over my abilities, that would come naturally.”

From "The Darkest Minds" by Alexandra Bracken

The “carry trade” of selling yen and earning interest on the money in dollars should have become less attractive as policy rates converged, strengthening the currency.

From The Wall Street Journal ● Aug. 6, 2026

The ultralow level of jobless claims is another sign of a gradually strengthening labor market and possibly even a growing shortage of labor.

From MarketWatch ● Aug. 6, 2026

Depending on the severity of a partial UCL tear, rehab and strengthening the muscles around the elbow can sometimes at least put off surgery.

From Los Angeles Times ● Aug. 5, 2026

"We made good progress strengthening BP's balance sheet," O'Neill said.

From Barron's ● Aug. 4, 2026

Because there was no snow, we pulled a four-wheeler with three sixteen-dog teams, strengthening them and training leaders, Corky watching from the windows as we ripped out of the kennel and into the trail system.

From This Side of Wild by Gary Paulsen

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023