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 (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

• 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

When Congress created the Federal Reserve System in 1913, lawmakers sought to diffuse power across 12 Federal Reserve district banks that were public-private hybrids with local boards consisting of local bankers, industrialists and community leaders.

From The Wall Street Journal • May 14, 2026

Evolutions in technology and the way wars are fought -- notably with drones -- are also making the global arms market more diffuse, which could benefit Japan, according to analysts at the Stimson Center.

From Barron's • May 3, 2026

Much of the Lakers bench and some coaches approached to help diffuse the situation.

From Los Angeles Times • Apr. 27, 2026

This structure shows that magnetized plasma is being dragged through the cluster, leaving behind a diffuse trail that has persisted for millions of years.

From Science Daily • Apr. 13, 2026

“If the wind blows south, then, the hurricane might miss the entire Gulf region. “If the hurricane loosens, becomes diffuse, then, there might be only a tropical storm for Florida, Mississippi, and Louisiana.

From "Ninth Ward" by Jewell Parker Rhodes