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

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

Newcastle need to strengthen the ageing spine of the side while there are also doubts surrounding the long-term futures of a number of key players, including midfielder Sandro Tonali.

From BBC • 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

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

The act of eating was a comfort to his shrunken belly, although a false one—the clover wouldn’t strengthen him.

From "Pax" by Sara Pennypacker

Related Words

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