Diffusion

Webster's Dictionary of the English Language

·noun The act of diffusing, or the state of being diffused; a spreading; extension; dissemination; circulation; dispersion.

II. Diffusion ·noun The act of passing by osmosis through animal membranes, as in the distribution of poisons, gases, ·etc., through the body. Unlike absorption, diffusion may go on after death, that is, after the blood ceases to circulate.