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