diffusion
noun
dif·fu·sion
di-ˈfyü-zhən 
1
: the state of being spread out or transmitted especially by contact : the action of diffusing
the diffusion of knowledge
2
3
a
chemistry
: the process whereby particles of liquids, gases, or solids intermingle as the result of their spontaneous movement caused by thermal (see thermal entry 1 sense 1b) agitation and in dissolved substances move from a region of higher to one of lower concentration
b
physics
(1)
: reflection of light by a rough reflecting surface
(2)
: transmission of light through a translucent material : scattering
4
: the spread of cultural elements from one area or group of people to others by contact
5
photography
: the softening of sharp outlines in an image
Examples of diffusion in a Sentence
the author's tendency toward diffusion makes the novel a tedious read
Recent Examples on the Web
Lighting plots drawn by diffusion models?
—
Seth Yudof, Rolling Stone, 28 Aug. 2025
The research team also pointed out that the strong physical correlation between capacity variability and three design parameters—solid-state diffusion coefficient, particle radius, and electrode thickness—during fast charging highlights their vital role in determining the degradation pathways.
—Prabhat Ranjan Mishra, Interesting Engineering, 24 Aug. 2025
The best of the bunch delivered fast, consistent warming, intuitive controls, and thoughtful extras like timer settings and scent diffusion.
—Maggie Horton, People.com, 24 Aug. 2025
That pattern matches the diffusion of innovation along an S‑curve—popularized by Everett Rogers—where a new technology works through successive segments of adopters.
—Christian Catalini, Forbes.com, 20 Aug. 2025
See All Example Sentences for diffusion
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Seth Yudof, Rolling Stone, 28 Aug. 2025
The research team also pointed out that the strong physical correlation between capacity variability and three design parameters—solid-state diffusion coefficient, particle radius, and electrode thickness—during fast charging highlights their vital role in determining the degradation pathways.
—Prabhat Ranjan Mishra, Interesting Engineering, 24 Aug. 2025
The best of the bunch delivered fast, consistent warming, intuitive controls, and thoughtful extras like timer settings and scent diffusion.
—Maggie Horton, People.com, 24 Aug. 2025
That pattern matches the diffusion of innovation along an S‑curve—popularized by Everett Rogers—where a new technology works through successive segments of adopters.
—Christian Catalini, Forbes.com, 20 Aug. 2025
See All Example Sentences for diffusion
Cite this Entry
“Diffusion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/diffusion. Accessed 5 Sep. 2025.
Copy CitationKids Definition
diffusion
noun
dif·fu·sion
dif-ˈyü-zhən
1
: a diffusing or a being diffused
2
: the mixing of particles of liquids, gases, or solids so that they move from a region of high concentration to one of lower concentration
3
: the scattering of light by reflection from a rough surface or by passage through a translucent material (as frosted glass)
Medical Definition
diffusion
noun
dif·fu·sion
dif-ˈyü-zhən
1
: the process whereby particles of liquids, gases, or solids intermingle as the result of their spontaneous movement caused by thermal agitation and in dissolved substances move from a region of higher to one of lower concentration
2
a
: reflection of light by a rough reflecting surface
b
: transmission of light through a translucent material
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