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

This new crisis will again strengthen the resolve of European countries and Canada to bolster their own defences and depend on themselves for their own security.

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

“The sword can destroy Horcruxes! Goblin-made blades imbibe only that which strengthen them—Harry, that sword’s impregnated with basilisk venom!”

From "Harry Potter and the Deathly Hallows" 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