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

It follows a $2.9 billion two-year investment Microsoft announced in 2024 to bolster the country's push into AI and strengthen its cyber defences.

From Barron's • Apr. 3, 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

He argued that closer ties with Europe would strengthen the UK's relationship with the US as well, since successive US presidents had been pushing for Europe to do more on defence and security.

From BBC • Apr. 1, 2026

She’ll have to make sure to add some crunches and leg lifts to strengthen her abdominals and her glutes.

From "A Heart in a Body in the World" by Deb Caletti

Related Words

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