diffusion

plural diffusions

1. countableuncountableThe act of diffusing or dispersing something, or the property of being diffused or dispersed; dispersion.
2. countableuncountablenatural sciencesThe scattering of light by reflection from a rough surface, or by passage through a translucent medium.
3. countableuncountablenatural sciencesThe intermingling of the molecules of a fluid due to random thermal agitation.

   gaseous diffusion

4. countableuncountableThe spread of cultural or linguistic practices, or social institutions, in one or more communities.

   Even the false-necked vase, though it reaches its widest diffusion at this epoch, is, as we have seen, a type found existing in much earlier strata.

   1907, Ronald M. Burrows, The Discoveries In Crete, page 99

5. countableuncountablebusinessThe gradual spread and adoption of goods or services.

   The chief salesman of the A.I. boom, Sam Altman of OpenAI, said there was more resistance to “the diffusion, the absorption” of A.I. into the culture and economy than he expected.

   2026 February 21, David Streitfeld, quoting Sam Altman, “People Loved the Dot-Com Boom. The A.I. Boom, Not So Much.”, in The New York Times, →ISSN

6. countableuncountableclimatologyExchange of airborne media between regions in space in an apparently random motion of a small scale.
7. countableuncountableThe movement of water vapor from regions of high concentration (high water vapor pressure) toward regions of lower concentration.