diffuse

American  

[dih-fyooz, dih-fyoos] / dɪˈfjuz, dɪˈfjus /

verb (used with object)

• diffuses,
  present (3rd person singular)
• diffused,
  past participle,  past
• diffusing
  present participle

1. to pour out and spread, as a fluid.

2. to spread or scatter widely or thinly; disseminate.

3. Physics. to spread by diffusion.

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verb (used without object)

• diffuses,
  present (3rd person singular)
• diffused,
  past participle,  past
• diffusing
  present participle

1. to spread.

2. Physics. to intermingle by diffusion.

adjective

1. characterized by great length or discursiveness in speech or writing; wordy.

2. widely spread or scattered; dispersed.

3. Botany. widely or loosely spreading.

4. Optics. (of reflected light) scattered, as from a rough surface (opposed to specular).

diffuse British  

/ dɪˈfjuːzəbəl, dɪˈfjuːslɪ /

verb

1. to spread or cause to spread in all directions

2. to undergo or cause to undergo diffusion

3. to scatter or cause to scatter; disseminate; disperse

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adjective

1. spread out over a wide area

2. lacking conciseness

3. (esp of some creeping stems) spreading loosely over a large area

4. characterized by or exhibiting diffusion

   diffuse light

   diffuse reflection

5. botany (of plant growth) occurring throughout a tissue

Commonly Confused

See defuse

Other Word Forms

Derived Forms

• diffuseness
  noun
• diffusibility
  noun
• overdiffuseness
  noun
• interdiffuse
  verb
• overdiffuse
  verb
• rediffuse
  verb
• diffusible
  adjective
• nondiffuse
  adjective
• nondiffused
  adjective
• nondiffusing
  adjective
• undiffused
  adjective
• well-diffused
  adjective
• diffusely
  adverb
• overdiffusely
  adverb

Inflected Forms

Participles

• diffusing
  present
• diffused
  past

Conjugated Forms

Present

• diffuse
  simple
• diffuses
  simple
• have diffused
  perfect
• has diffused
  perfect
• am diffusing
  progressive
• are diffusing
  progressive
• is diffusing
  progressive
• have been diffusing
  perfect progressive
• has been diffusing
  perfect progressive

Past

• diffused
  simple
• had diffused
  perfect
• was diffusing
  progressive
• were diffusing
  progressive
• had been diffusing
  perfect progressive

Future

• will diffuse
  simple
• will have diffused
  perfect
• will be diffusing
  progressive
• will have been diffusing
  perfect progressive

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Etymology

Origin of diffuse

1350–1400; Middle English (< Anglo-French ) < Latin diffūsus spread, poured forth. See dif-, fuse ²

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Explanation

Diffuse means to spread out. Candlelight can diffuse a soft glow throughout a room. A diffuse idea is one that spreads from person to person, and a diffuse speech is scattered and unclear. As a verb, diffuse means to spread something out, but also applies to spreading things such as ideas or culture so that they become widely known. When something is diffused, it's mixed in, and when you drop propaganda pamphlets out of airplanes you're diffusing the propaganda. The adjective comes from Latin diffusus, from diffundere "to pour in different directions," from the prefix dis- "apart" plus fundere, "to pour."

Example Sentences

See Examples For:

diffuse diffuses diffused diffusing

Known as intracluster light, this diffuse glow comes from stars scattered into the spaces between galaxies.

From Science Daily ● Oct. 13, 2026

Derivatives and securitizations, whose volumes remain high, diffuse risk through the financial system but also link entities in daisy chains of risk.

From MarketWatch ● Sep. 23, 2026

It takes something diffuse — access to a vast collection of things you do not personally have to own — and renders it in the language of a grocery receipt.

From Salon ● Sep. 6, 2026

Palo Alto also notched around 220 net “platformizations” during the quarter, referring to customers who upgrade diffuse cybersecurity measures into a single platform.

From The Wall Street Journal ● Sep. 1, 2026

A fiery outline of twilight shone around her silhouette, burned red-gold in her hair, grew diffuse in the fuzzy texture of the woolen skirt pulled carelessly about her knees.

From "The Secret History" by Donna Tartt

The glass is screened by adjustable curtains of a high-tech fabric that diffuses and softens the sunlight, making it ideal for viewing the three-dimensional art displayed there.

From The Wall Street Journal ● Apr. 17, 2026

They’re also less likely to be cultivated in complete monocultures than oil palms, which diffuses their impact on surrounding ecosystems.

From Salon ● Jul. 29, 2024

Dunst diffuses the moment by adopting an exaggerated Valley girl sing-song, “I basically fell in love with Cailee and I was like, ‘She’s the best, you need to work with her.’”

From Los Angeles Times ● Apr. 4, 2024

It borrows an idea from physics that can be used to describe, for instance, how gas diffuses outward.

From Seattle Times ● Mar. 4, 2024

The square of sunshine moves, diffuses, grows faint yellow.

From "The Boy Who Dared" by Susan Campbell Bartoletti

Xu and team argue that any systems breakthrough or efficiency gains are diffused quickly across the ecosystem.

From MarketWatch ● Feb. 16, 2026

Minnesota’s missing treasurer produced a costly lesson about what happens when financial authority is diffused and accountability disappears.

From The Wall Street Journal ● Dec. 22, 2025

“Oprah’s Favorite Things was a phenomenon because of how trusted Oprah was, so it really is that same phenomenon, just diffused across the creator ecosystem.”

From Los Angeles Times ● Oct. 18, 2025

Draper quickly diffused what could have been a tricky encounter, showing his superior quality and experience from the start.

From BBC ● May 31, 2025

But because the light travels such a long distance, the magic in it is fragile and diffused, stretched into the most delicate of threads.

From "The Girl Who Drank the Moon" by Kelly Barnhill

“The S&P and mega cap complex have felt strangely heavy without a great fundamental reason. Worth keeping in the back of the mind that some leverage/carry may simply be diffusing out of the system.”

From MarketWatch ● Sep. 9, 2026

Add to this growing critical mineral-processing capacity, vast AI training data generated by India’s large population, and the potential role of Indian IT companies in diffusing AI to less technologically advanced economies.

From The Wall Street Journal ● Jul. 1, 2026

Participants will be working on shared language for annexes covering child protection, AI security and governance and diffusing AI through economies -- especially to small and medium firms.

From Barron's ● May 29, 2026

Every time you say, “Let them,” even if it’s after the outburst, you’re still diffusing the emotion.

From Los Angeles Times ● Mar. 5, 2025

There, Margaret, the sun is for ever visible, its broad disk just skirting the horizon and diffusing a perpetual splendour.

From "Frankenstein" by Mary Shelley

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