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

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 Others think it’s all fake, and trailer 2 will further reinforce their beliefs. Chris Smith, BGR, 17 Nov. 2021 The images also can reinforce witness statements, Litwin said. Jesse Leavenworth,, 28 Oct. 2021 The second is that punishments themselves, even when justified, could reinforce existing implicit and explicit biases. Amelia Wirts, The Conversation, 15 Oct. 2021 Eateries and other commercial establishments currently required to close early should return to normal hours gradually while the authorities reinforce health care systems to prepare for the next outbreak, officials said., 27 Sep. 2021 Madrid said that a Newsom win would reinforce the diminishing relevance of Republicans in the state as that far-right flank becomes the party’s core, and could spark more recall attempts. Los Angeles Times, 12 Sep. 2021 The new troops, who will reinforce about 650 troops left as diplomatic security at the embassy and the airport, are not to get involved in the Afghan government's war with the Taliban, Kirby said. Compiled Democrat-gazette Staff From Wire Reports, Arkansas Online, 13 Aug. 2021 Overhead, a system of hanging battens, or strips of wood, will be organized in wave patterns designed to reinforce the main pathways through exhibits, while subtly referring to the idea of rippling streams. Steven Litt, cleveland, 9 Jan. 2022 In Indiana, where the National Guard was called in to reinforce hospital staffs, administrators offer double pay to workers who extend their shifts when colleagues are sick. Compiled Democrat-gazette Staff From Wire Reports, Arkansas Online, 9 Jan. 2022

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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Dictionary Entries Near reinforce



reinforced bow

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Statistics for reinforce

Last Updated

25 Jan 2022

Cite this Entry

“Reinforce.” Dictionary, Merriam-Webster, Accessed 28 Jan. 2022.

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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

More from Merriam-Webster on reinforce

Nglish: Translation of reinforce for Spanish Speakers

Britannica English: Translation of reinforce for Arabic Speakers


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