diffuse

American  

[dih-fyooz, dih-fyoos] / dɪˈfyuz, dɪˈfyus /

verb (used with object)

diffused, diffusing

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)

diffused, diffusing

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 (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

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

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

“Just talking through it with the people that are actually helping to diffuse AI through the economy across every single industry” is “exactly what we’re going to continue to do,” Hays added.

From MarketWatch • Apr. 3, 2026

“My worry is about whether the benefits of AI will diffuse to all people.”

From The Wall Street Journal • Mar. 11, 2026

Further analysis combining data from Hubble, Euclid, and Subaru uncovered a faint, diffuse glow surrounding the clusters.

From Science Daily • Feb. 21, 2026

In order to further diffuse tensions, Zubaidi and an STC delegation had been due to fly from Aden to Riyadh on Tuesday night for talks with the government.

From BBC • Jan. 7, 2026

Conversely, Eurasian crops that were first domesticated far from the Fertile Crescent but at the same latitudes were able to diffuse back to the Fertile Crescent.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond