Diffusion is a time-dependent random process causing a spread in space. Diffusion may also refer to: Physical sciences Molecular diffusion, spontaneous dispersion of mass (distinct from migration, caused by an external force) Conduction of heat Momentum diffusion Diffusion equation Heat equation Eddy diffusion More specific meanings Anomalous diffusion, the movement of particles from a region of lower concentration to a region of higher concentration Diffusion MRI Diffusion (acoustics), sound waves Atomic diffusion Brownian motion Collective diffusion Facilitated diffusion Effusion of a gas through small holes Gaseous diffusion Itō diffusion Knudsen diffusion of particles from very small containers Osmosis, the movement of molecules through a membrane Reverse osmosis, a process to separate unwanted particles from a fluid Photon diffusion, an optical effect Diffuse reflection, the reflection of light from an uneven or granular surface Reverse diffusion, the movement of particles from a region of lower concentration to a region of higher concentration Rotational diffusion Self-diffusion Surface diffusion Thermodiffusion Social sciences Diffusion of innovations within a society or a culture or between them Lexical diffusion within a culture Trans-cultural diffusion of culture items between cultures Technology Diffusion (cryptography), the spreading of influence of bits in a cipher Error diffusion in image processing Diffusion model in machine learning image generation. Other uses Diffusion (business), the process by which a new idea or new product is accepted by the market Diffusion line, a secondary line of merchandise created by a high-end fashion designer Diffusion Pharmaceuticals, a drug development company Diffusion process, in probability theory the solution to a stochastic differential equation Diffusion of responsibility Society for the Diffusion of Useful Knowledge Diffusion Science Radio Show, a science radio show and podcast on 2SER in Sydney Diffusion Records, an independent record label Sound diffusion, a performance practice in electronic music See also Diffuser (disambiguation) Diffuse nebula Migration (disambiguation)