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

: prolixity, diffuseness

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

diffusional

di-ˈfyü-zhə-nᵊl 

adjective

Synonyms

• circumlocution
• diffuseness
• garrulity
• garrulousness
• logorrhea
• long-windedness
• periphrasis
• prolixity
• redundancy
• verbalism
• verbiage
• verboseness
• verbosity
• windiness
• wordage
• wordiness

Examples of diffusion in a Sentence

the author's tendency toward diffusion makes the novel a tedious read

Recent Examples on the Web

Nvidia should be using its success around the world to work hard to compete against China in other markets and stop focusing on its diminishing market share in China, especially after Trump gave the company the gift of repelling the AI diffusion rule. —Dewardric L. McNeal, CNBC, 29 May 2025

The color, the pizzazz, the spectacle is what has drawn so many of us to the handiwork of the LLM in a diffusion model, where the program adds noise, prior to de-noising into a novel, coherent result. —John Werner, Forbes.com, 29 May 2025

On a post-earnings-release call, CEO Jensen Huang said there are four positive surprises so far in 2025: the demand of reasoning AI, the removal of the AI diffusion rule, enterprise AI, and industrial AI. —Shannon Carroll, Quartz, 28 May 2025

The diffusion rule was more than just a mere export control. —Matthew Mittelsteadt, National Review, 26 May 2025

Word History

Etymology

Middle English diffusioun "outpouring (of speech)," borrowed from Late Latin diffūsiōn-, diffūsiō "pouring out (of liquids), watering of the eyes, abundance" (Latin, "geniality"), from Latin diffud-, variant stem of diffundere "to pour out over a wide surface, spread out, extend" + -tiōn-, -tiō, suffix of verbal action — more at diffuse entry 2

First Known Use

15th century, in the meaning defined at sense 2

Rhymes for diffusion

• allusion
• collusion
• conclusion
• confusion
• contusion
• delusion
• effusion
• exclusion
• extrusion
• illusion
• inclusion
• infusion

Kids 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

diffusional

-ˈyüzh-nəl, -ən-ᵊl 

adjective