dif·​fuse | \ di-ˈfyüs How to pronounce diffuse (audio) \

Definition of diffuse

 (Entry 1 of 2)

1 : being at once verbose and ill-organized a diffuse report from the scene of the earthquake
2 : not concentrated or localized diffuse lighting diffuse sclerosis


dif·​fuse | \ di-ˈfyüz How to pronounce diffuse (audio) \
diffused; diffusing

Definition of diffuse (Entry 2 of 2)

transitive verb

1a : to pour out and permit or cause to spread freely a drop of blue dye diffused in a glass of water
b : extend, scatter diffusing their ideas throughout the continent
c : to spread thinly or wastefully a government in which power is diffused
2 physics : to subject to diffusion (see diffusion sense 3) especially : to break up and distribute (incident light) by reflection put up a screen to diffuse the light

intransitive verb

1 : to spread out or become transmitted especially by contact The civilization diffused westward.
2 : to undergo diffusion heat from the radiator diffusing throughout the room

Other Words from diffuse


diffusely adverb
diffuseness noun


diffusible \ di-​ˈfyü-​zə-​bəl How to pronounce diffuse (audio) \ adjective

Choose the Right Synonym for diffuse


wordy, verbose, prolix, diffuse mean using more words than necessary to express thought. wordy may also imply loquaciousness or garrulity. a wordy speech verbose suggests a resulting dullness, obscurity, or lack of incisiveness or precision. the verbose position papers prolix suggests unreasonable and tedious dwelling on details. habitually transformed brief anecdotes into prolix sagas diffuse stresses lack of compactness and pointedness of style. diffuse memoirs that are so many shaggy-dog stories

Frequently Asked Questions About diffuse

What is the difference between diffuse and defuse?

Many people find it difficult to remember the difference between defuse and diffuse, and when faced with the need for one of these words simply grab whichever one first comes to mind. Although these word sound quite similar, their meanings are rather distinct. Defuse means "to make less harmful, potent, or tense"; the word has another, helpfully literal, meaning, which is "to remove the fuse from." Diffuse means "not concentrated or localized"; it comes from the Latin word diffūsus ("spread over a wide area").

What is the difference between diffuse and infuse?

Diffuse is commonly found used as both adjective ("not concentrated or localized") and verb ("to pour out and permit or cause to spread freely," "to scatter"), while infuse is almost entirely restricted to use as a verb. While the meannings of diffuse are mainly concerned with outward movement, those of infuse are inward; the word has such meanings as "to steep in liquid (such as water) without boiling so as to extract the soluble constituents or principles," "to administer or inject by infusion," and "to cause to be permeated with something (such as a principle or quality) that alters usually for the better."

What does diffuse pain mean?

Diffuse pain is pain is pain that not concentrated or localized, being instead spread throughout a wider area of the body.

Examples of diffuse in a Sentence

Adjective The forest was filled with a soft, diffuse light. a diffuse speech that took a great deal of time to make a very small point Verb The heat from the radiator diffuses throughout the room. The heat was diffused throughout the room. The photographer uses a screen to diffuse the light. an area of diffused light See More
Recent Examples on the Web: Adjective First, there are two ultra-diffuse galaxies that appear to be satellite members of a massive group dominated by NGC 1052: DF2 and DF4. Ethan Siegel, Forbes, 22 June 2021 In Los Angeles County, the impacts of the pandemic have been relatively diffuse, with millions of residents suffering and grieving in isolation across a famously vast sprawl. Matthew Bloch, New York Times, 29 Jan. 2021 In large part, that’s because the CO2 in power plant emissions is relatively diffuse. Tim Mcdonnell, Quartz, 13 Aug. 2020 Kraftwerk’s studio albums have been sampled liberally (by Jay-Z, Afrika Bambaataa, Coldplay), but its influence feels even more diffuse and profound. Amanda Petrusich, The New Yorker, 6 May 2020 Like one of the smooth wood sculptures inside, its solid form twists and in some cases fractures, opening up large skylights that bring diffuse illumination into the galleries. Sam Lubell, Los Angeles Times, 2 Apr. 2020 In the United States, a younger and more diffuse population means the peak comes a bit later and doesn't rise as high per capita, but the larger population means that over 2 million people end up dead. John Timmer, Ars Technica, 17 Mar. 2020 Artificial light includes both direct lighting, such as street lights and commercial signs, and skyglow, a more diffuse illumination that spreads beyond urban centers and can be brighter than a full moon. Katie Hunt, CNN, 3 Feb. 2020 The image captures a wide array of phenomena; some fall under the category of halos, while the more diffuse shadings closer to the moon are from a corona. Washington Post, 11 Jan. 2020 Recent Examples on the Web: Verb Wg proteins themselves do not diffuse widely from their place of origin in the brain. William A. Haseltine, Forbes, 11 July 2022 Lauren died of something horrible, diffuse intrinsic pontine glioma, a type of incurable brain tumor that preys on children. Paul Daugherty, The Enquirer, 26 June 2022 But even when the battery is not in use, the ions gradually diffuse across this material, which is called the electrolyte. Anna Blaustein, Scientific American, 6 May 2022 It’s this uncertainty that makes our fears feel impossible to act on, that keeps us locked in contradictions and diffuse worry. Lily Houston Smith, The Atlantic, 23 June 2022 In another effort to diffuse the situation, President Joe Biden on Wednesday invoked the Defense Production Act to prioritize ingredients needed for formula production. Byalexandra Hutzler, ABC News, 20 May 2022 This will help the fridge diffuse heat better and run more efficiently. Mimi Montgomery, Washington Post, 28 June 2022 Stay calm, rational and collected by adding the neurochemical oxytocin to diffuse the situation: Take deep breaths with full exhalation to regulate your blood pressure, reduce your fear response and uncover the opportunities. Expert Panel®, Forbes, 23 May 2022 Head coach Monty Williams tried to diffuse the Suns’ humbling loss, instead attempting to take the blame rather than placing it on the players. Dj Siddiqi, Forbes, 16 May 2022 See More

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

First Known Use of diffuse


1612, in the meaning defined at sense 1


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

History and Etymology for diffuse


Middle English, "dispersed, verbose (of speech or writing)," borrowed from Middle French & Latin; Middle French diffus, borrowed from Latin diffūsus "spread over a wide area, (of writing) extensive, verbose," from past participle of diffundere "to pour out over a wide surface, spread, extend, squander" — more at diffuse entry 2


Middle English, in past participle diffusid, borrowed from Latin diffūsus, past participle of diffundere "to pour out over a wide surface, spread out, extend, squander," from dif-, assimilated form of dis- dis- + fundere "to pour, shed" — more at found entry 5

Learn More About diffuse

Time Traveler for diffuse

Time Traveler

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

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Dictionary Entries Near diffuse



diffuse nebula

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Cite this Entry

“Diffuse.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/diffuse. Accessed 13 Aug. 2022.

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More Definitions for diffuse


dif·​fuse | \ di-ˈfyüz How to pronounce diffuse (audio) \
diffused; diffusing

Kids Definition of diffuse

: to spread or allow to spread freely The frosted window diffused the sunlight.


dif·​fuse | \ dif-ˈyüs How to pronounce diffuse (audio) \

Medical Definition of diffuse

 (Entry 1 of 2)

: not concentrated or localized diffuse sclerosis


dif·​fuse | \ dif-ˈyüz How to pronounce diffuse (audio) \
diffused; diffusing

Medical Definition of diffuse (Entry 2 of 2)

transitive verb

1 : to subject (as a light beam) to diffusion
2 : to break up and distribute (incident light) by reflection (as from a rough surface)

intransitive verb

: to undergo diffusion

More from Merriam-Webster on diffuse

Nglish: Translation of diffuse for Spanish Speakers

Britannica English: Translation of diffuse for Arabic Speakers


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