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

Getty had alleged that London-based Stability AI, whose directors include Canadian filmmaker James Cameron, "extracted millions" of images from Getty's websites "without consent" to unlawfully train its deep learning AI model, Stable Diffusion.

From Barron's • Nov. 4, 2025

One of the early documents that Mr. Cheshire found is an atlas produced by the Society for the Diffusion of Useful Knowledge between 1829 and 1844.

From The Wall Street Journal • Oct. 31, 2025

Stability AI founder Emad Mostaque has previously told BBC News Stable Diffusion is trained using "100,000 GB of images" taken from the internet.

From BBC • Sep. 25, 2024

Diffusion models, often used for image generation, learn to create new data samples that resemble samples in a training dataset by iteratively refining their output.

From Science Daily • Jun. 3, 2024

Diffusion worked as a “cascade”—in steps, with each cycle of diffusion incrementally increasing the concentration of U-235 in the feedstock produced by the previous cycles.

From "Big Science" by Michael Hiltzik

Related Words

• dispersal
• dispersion
• dissemination
• dissipation