re·​in·​force | \ ˌrē-ən-ˈfȯrs How to pronounce reinforce (audio) \
variants: or less commonly
reinforced also reenforced; reinforcing also reenforcing; reinforces also reenforces

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 reinforce (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 Oftentimes, companies spend thousands to bring in an outside firm or consultant to teach a new technique, but then only reinforce it for a few weeks. Expert Panel®, Forbes, "15 Business Leaders Share Their Most Effective Sales Training Techniques," 28 Apr. 2021 Many used the sturdy, precut stones to build animal pens or reinforce their tents. New York Times, "Fleeing a Modern War, Syrians Seek Refuge in Ancient Ruins," 19 Apr. 2021 In addition to speaking about the points of friction, a summit would help the two nuclear-armed countries find ways to deal with their differences, and potentially reinforce areas of common interest. Frida Ghitis, CNN, "Putin and Biden are circling each other warily," 15 Apr. 2021 His occasional fast-break dunks or rundown blocks reinforce as much. Connor Letourneau, San Francisco Chronicle, "Warriors' James Wiseman suffers torn meniscus, could miss rest of season," 11 Apr. 2021 Yet the dominant narrative in Lithuania has long been one of resistance to both the Soviets and the Nazis, a hallmark of national identity that state officials have worked to reinforce. NBC News, "How a Chicago teacher sparked a 'memory war,' forcing Lithuania to confront its Nazi past," 4 Apr. 2021 The irony is that, at least in the near term, China’s assertive response seems likely to reinforce rather than erode cohesion between Washington and its allies. Ned Temko, The Christian Science Monitor, "Biden wants to beat China. Beijing says, bring it on.," 1 Apr. 2021 These algorithms detect that and reinforce it, selecting content that sends us down increasingly negative rabbit holes. Time, "Disinformation Is Among the Greatest Threats to Our Democracy. Here Are Three Key Ways to Fight It," 5 Mar. 2021 In his letter, Smith noted that there are steps the DOD must take in order to separate the NSA and CYBERCOM – a measure Congress actually worked to reinforce in 2019 following chatter about a potential split, reported Defense News. Caitlin Mcfall, Fox News, "Defense officials look at splitting up NSA, CYBERCOM," 19 Dec. 2020

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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Time Traveler for reinforce

Time Traveler

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

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Statistics for reinforce

Last Updated

1 May 2021

Cite this Entry

“Reinforce.” Dictionary, Merriam-Webster, Accessed 6 May. 2021.

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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 reinforce (audio) \ adjective

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Comments on reinforce

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