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

Etymology

Origin of diffuse

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

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

When disturbed, it can be inhaled which can cause serious diseases and cancer, like diffuse mesothelioma.

From BBC ● Aug. 20, 2026

Third, Chandra detected only very weak diffuse X-ray emission.

From Science Daily ● Aug. 2, 2026

An attempt to detonate or diffuse the bomb failed, so Officer Brian Murray and three others were lowered into the crater.

From Slate ● Jul. 7, 2026

Political economist Mancur Olson explained why these benefits are overlooked: Concentrated, tangible interests prevail over much larger diffuse ones.

From The Wall Street Journal ● Jun. 24, 2026

The clouds present diffuse bands of tender grays and blues, and below them the ocean does the same.

From "All the Light We Cannot See" by Anthony Doerr

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

Now it does get diffused in the end, after the sheriffs come in and convince the young guys to go home.

From Salon ● Sep. 3, 2024

Of course there are still parades of contention, but this situation has by-in-large been completely diffused.

From BBC ● Jun. 20, 2024

When she lit the gas, there was a soft diffused light without glare.

From "A Tree Grows in Brooklyn" by Betty Smith

To oversee this more complex economy, reformers turned to specialized bodies of experts and—echoing the founders’ instinct for diffusing power—insulated them from politics.

From The Wall Street Journal ● Jul. 4, 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

With that key narrative element out in the open, the movie’s beats are all too easy to predict, diffusing what little humor there was left to garner from its meager amount of twists.

From Salon ● Jan. 31, 2025

The jolt spread lower and lower, into his stomach, like droplets of blood diffusing into water.

From "The Serpent King" by Jeff Zentner