re·​in·​force | \ ˌrē-ən-ˈfȯrs How to pronounce reinforce (audio) \
variants: or less commonly

Definition of reinforce

transitive verb

1 : to strengthen by additional assistance, material, or support : make stronger or more pronounced reinforce levees reinforce the elbows of a jacket reinforce ideas
2 : to strengthen or increase by fresh additions reinforce our troops were reinforcing their pitching staff
3 : to stimulate (a subject, such as an experimental animal) by reinforcement (see reinforcement sense 3) also : to encourage (a response) by reinforcement

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Other Words from reinforce

reinforceable \ ˌrē-​ən-​ˈfȯr-​sə-​bəl How to pronounce reinforceable (audio) \ adjective

Examples of reinforce in a Sentence

The captain sent out another squad to reinforce the troops. Our camp is reinforced with supplies flown in by helicopter. The levees will need to be reinforced. The bad weather forecast only reinforces our decision to leave early tomorrow. Some critics say that the movie reinforces negative stereotypes about the military. We do our best to reinforce good conduct in the classroom.
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Recent Examples on the Web

Though workers have drawn annual profit-sharing checks, the union says G.M. has done too little to repay employees for past concessions and to reinforce their job security. Erin Kirkland, New York Times, "What the G.M. Strike Looks Like," 16 Sep. 2019 After being in a band that played at places like the White House for President Obama, Coachella, Red Rocks and Wembley Stadium, watching Keuning take things back to square one only seemed to reinforce his true passion for the new material. San Diego Union-Tribune, "Review: At KAABOO, ex-Killer Dave Keuning plays from the heart in his biggest hometown solo show yet," 15 Sep. 2019 Decades after abolitionists had first pointed to the original privileges-and-immunities clause as an anti-slavery guarantee, the new amendment added a second one to reinforce these rights against state oppression. Timothy Sandefur, National Review, "The Anti-Slavery Constitution," 12 Sep. 2019 But Arena benched Caicedo, adding Jalil Anibaba to reinforce the defense midway through the opening half., "Antonio Delamea," 11 Sep. 2019 On Saturday, crews were working to reinforce containment lines in preparation for thunderstorms in the area Sunday and Monday, officials said. Chelsea Curtis, azcentral, "3 lightning-caused fires see growth overnight in Tonto National Forest," 7 Sep. 2019 Her inflammatory opinions also have been embraced by President Donald Trump, who has a history of retweeting her comments to reinforce some of his views on migrants and on Islam. Martha Ross, The Mercury News, "‘Racist’ ‘hit piece’ on Meghan Markle slammed for featuring favorite Trump commentator," 6 Sep. 2019 This cynical, Manichean take on history, like cultural appropriation, slavery reparations, intersectionality, and other expressions of identity politics, serve only to reinforce divisions. Krista Kafer, The Denver Post, "Kafer: A lesson on identity politics from the Dominican Republic," 5 Sep. 2019 The expedition sought to both explore the North Pacific Ocean and to reinforce America’s commitment to trade with Asia. Smithsonian, "The Hard-Drinking Early Smithsonian Naturalists of the Megatherium Club," 4 Sep. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'reinforce.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of reinforce

15th century, in the meaning defined at transitive sense 1

History and Etymology for reinforce

re- + inforce, alteration of enforce

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Statistics for reinforce

Last Updated

7 Oct 2019

Look-up Popularity

Time Traveler for reinforce

The first known use of reinforce was in the 15th century

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More Definitions for reinforce



English Language Learners Definition of reinforce

: to strengthen (a group of people) with new supplies or more people
: to strengthen (something, such as clothing or a building) by adding more material for support
: to encourage or give support to (an idea, behavior, feeling, etc.)


re·​in·​force | \ ˌrē-ən-ˈfȯrs\
reinforced; reinforcing

Kids Definition of reinforce

1 : to strengthen with new supplies or more people Another squad reinforced the troops.
2 : to strengthen by adding more material for support The wall needs to be reinforced.


transitive verb
re·​in·​force | \ ˌrē-ən-ˈfō(ə)rs, -ˈfȯ(ə)rs How to pronounce reinforce (audio) \
reinforced; reinforcing

Medical Definition of reinforce

1 : to strengthen by additional material or support : make stronger reinforced with vitamins
2 : to stimulate (as an experimental animal or a student) by reinforcement also : to encourage (a response) by reinforcement

Other Words from reinforce

reinforceable \ -​ə-​bəl How to pronounce reinforceable (audio) \ adjective

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