diffusion

ot noun

1. The act of diffusing or dispersing something, or the property of being diffused or dispersed; dispersion.
2. The scattering of light by reflection from a rough surface, or by passage through a translucent medium.
3. The intermingling of the molecules of a fluid due to random thermal agitation.
4. The spread of cultural or linguistic practices, or social institutions, in one or more communities.