/di fyooh"zheuhn/ , n.
1. act of diffusing; state of being diffused.
2. prolixity of speech or writing; discursiveness.
3. Physics.
a. Also called migration . an intermingling of molecules, ions, etc., resulting from random thermal agitation, as in the dispersion of a vapor in air.
b. a reflection or refraction of light or other electromagnetic radiation from an irregular surface or an erratic dispersion through a surface; scattering.
4. Motion Pictures. a soft-focus effect resulting from placing a gelatin or silk plate in front of a studio light or a camera lens, or through the use of diffusion filters.
5. Meteorol. the spreading of atmospheric constituents or properties by turbulent motion as well as molecular motion of the air.
6. Anthropol. , Sociol. the transmission of elements or features of one culture to another.
[ 1325-75; ME diffusion- (s. of diffusio ) a spreading out, equiv. to diffus ( us ) (see DIFFUSE) + -ion- -ION ]