- (physics) the intermingling of the molecules of a fluid due to random thermal agitation
- the movement of water vapor from regions of high concentration (high water vapor pressure) toward regions of lower concentration.
- (physics) the scattering of light by reflection from a rough surface, or by passage through a translucent medium
- (physics, weather) Exchange of airborne media between regions in space in an apparently random motion of a small scale.
- the act of diffusing or dispersing something, or the property of being diffused or dispersed; dispersion
- the spread of cultural or linguistic practices, or social institutions, in one or more communities