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

The U.S. company said it would strengthen a tie-up with the country’s cybersecurity office and help the government and businesses detect cyberattacks early or preempt them.

From The Wall Street Journal • Apr. 3, 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

This deal would strengthen McCormick’s condiments and flavorings portfolio while expanding its North American retail and distribution footprint, said Alex Torgerson, M&A partner at consulting firm West Monroe.

From Barron's • Mar. 31, 2026

These tube-like materials can strengthen polymers and metals or guide the movement of ions in batteries and desalination systems with far less resistance.

From Science Daily • Mar. 31, 2026

“Oh? Your father wouldn’t command you to marry some princess in order to strengthen his empire?”

From "Throne of Glass" by Sarah J. Maas

Related Words

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