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

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

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

If demand holds up, Citi economists expect China’s status as the “world’s factory” to strengthen.

From The Wall Street Journal • 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

As freedom fighters and political prisoners, we had an obligation to improve and strengthen ourselves, and study was one of the few opportunities to do so.

From "Long Walk to Freedom" by Nelson Mandela

Related Words

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