Definition of "diffusion"

The act of diffusing or dispersing something, or the property of being diffused or dispersed; dispersion.  examples

(physics) The scattering of light by reflection from a rough surface, or by passage through a translucent medium.  examples

(physics) The intermingling of the molecules of a fluid due to random thermal agitation.  examples

The spread of cultural or linguistic practices, or social institutions, in one or more communities.  examples

(marketing) The gradual spread and adoption of goods or services.  examples

(physics, weather) Exchange of airborne media between regions in space in an apparently random motion of a small scale.  examples

The movement of water vapor from regions of high concentration (high water vapor pressure) toward regions of lower concentration.  examples