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.

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verb (used without object)

1. to gain strength; grow stronger.

strengthen British  

/ ˈstrɛŋθən /

verb

1. to make or become stronger

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Other Word Forms

• overstrengthen verb
• prestrengthen verb (used with object)
• restrengthen verb
• strengthener noun
• strengtheningly adverb
• unstrengthened adjective
• unstrengthening adjective

Etymology

Origin of strengthen

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

Example Sentences

“At a time of rampant threats to our democratic system, we must strengthen and defend the integrity of our elections to reaffirm that our government is of, by, and for the people,” she said.

From Los Angeles Times • Apr. 4, 2026

While supporters argue that restarting drilling would strengthen security and energy independence, experts interviewed by AFP emphasised major constraints for both oil and gas.

From Barron's • Apr. 1, 2026

"I do think that we should strengthen our cooperation on defence, security, energy, emissions and the economy," he replied.

From BBC • Apr. 1, 2026

If we limit service to the battlefield, we overlook the millions who strengthen this country in other meaningful ways.

From The Wall Street Journal • Mar. 31, 2026

“They can strengthen, you know, the longer they’re kept.”

From "Harry Potter and the Half-Blood Prince" by J.K. Rowling

Related Words

• bolster
• build up
• enhance
• enlarge
• establish
• extend
• heighten
• increase
• intensify
• invigorate
• reinforce
• restore
• set up
• step up
• support
• sustain
• toughen