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

"What we want to do is to strengthen Europe's defence within the Atlantic alliance," French armed forces minister Alice Rufo said.

From Barron's • Apr. 1, 2026

Intel expects the transaction to add to ongoing earnings per share and strengthen the company’s credit profile beginning in 2027.

From The Wall Street Journal • 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

Her findings were sent to the FBI, and the prosecution used them to strengthen their case.

From "The Woman All Spies Fear" by Amy Butler Greenfield

Related Words

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