diffusion

American  

[dih-fyoo-zhuhn] / dɪˈfyu ʒən /

noun

1. the act of diffusing or state of being diffused.

   During the gradual, unorchestrated diffusion of ideas from science into the surrounding culture, crucial information can sometimes be lost.

2. excessive wordiness of speech or writing; long-windedness.

3. Physics.

   1. Also called migration.  an intermingling of molecules, ions, etc., resulting from random thermal agitation, as in the dispersion of a vapor in air.

   2. a reflection or refraction of light or other electromagnetic radiation from an irregular surface, or an erratic dispersion through a surface; scattering.

4. Movies. a soft-focus effect resulting from placing a gelatin or silk plate in front of a studio light or a camera lens, or through the use of diffusion filters.

5. Meteorology. the spreading of atmospheric constituents or properties by turbulent motion as well as molecular motion of the air.

6. Also called cultural diffusion.  Anthropology, Sociology. the transmission of elements or features of one culture to another.

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diffusion British  

/ dɪˈfjuːʒən /

noun

1. the act or process of diffusing or being diffused; dispersion

2. verbosity

3. physics

   1. the random thermal motion of atoms, molecules, clusters of atoms, etc, in gases, liquids, and some solids

   2. the transfer of atoms or molecules by their random motion from one part of a medium to another

4. physics the transmission or reflection of electromagnetic radiation, esp light, in which the radiation is scattered in many directions and not directly reflected or refracted; scattering

5. Also called: diffusivity.  physics the degree to which the directions of propagation of reverberant sound waves differ from point to point in an enclosure

6. anthropol the transmission of social institutions, skills, and myths from one culture to another

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diffusion Scientific  

/ dĭ-fyo̅o̅′zhən /

1. The movement of atoms or molecules from an area of higher concentration to an area of lower concentration. Atoms and small molecules can move across a cell membrane by diffusion.

2. Compare osmosis

3. The reflection or refraction of radiation such as light or sound by an irregular surface, tending to scatter it in many directions.

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diffusion Cultural  

1. The spreading of atoms or molecules of one substance through those of another, especially into liquids or gas es.

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Other Word Forms

• interdiffusion noun
• nondiffusion noun
• overdiffusion noun
• rediffusion noun
• self-diffusion noun

Etymology

Origin of diffusion

First recorded in 1325–75; Middle English, from Latin diffūsiōn-, stem of diffūsiō “a spreading out”; equivalent to diffuse + -ion

Explanation

Diffusion is the act of dispersing something, spreading it out from a central point. When an idea catches on, that's a type of diffusion. When you spray air freshener and the scent spreads from a tight space to fill a larger one, that's diffusion. In science, diffusion is a physical process of atoms or molecules moving apart within a gas or liquid. You can also use the word diffusion to describe the spreading of information. Ever notice how a trendy word or band will suddenly be everywhere, even though nobody heard of it last week? That's diffusion. This word means something similar to dispersal and dissemination.

Example Sentences

“The diffusion curve in AI is happening twice as quickly….we think you’ll go from basically a billion people using these tools to four to five billion.”

From Barron's • Apr. 10, 2026

“The light in the sky is actually bouncing off the clouds, so the clouds are a diffusion rather than a straight-up hard light source.”

From The Wall Street Journal • Mar. 22, 2026

“Multiple industry players over time, particularly Nvidia, have argued that smuggling or diffusion of AI technologies to China were tall tales,” Burnham said.

From MarketWatch • Mar. 21, 2026

These vibrations mix electronic states and effectively push the electron across the boundary, creating a directional, ballistic motion instead of slow and random diffusion.

From Science Daily • Mar. 6, 2026

Quantitative data should also be assembled to test my preliminary calculations suggesting differing rates of diffusion along the major axes of Eurasia, the Americas, and Africa.

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

Related Words

• dispersal
• dispersion
• dissemination
• dissipation