natural philosophy, physical science, physics - the science of matter and energy and their interactions

natural action, natural process, activity, action - a process existing in or produced by nature (rather than by the intent of human beings); "the action of natural forces"; "volcanic activity"

osmosis - diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal

permeation, pervasion, suffusion - the process of permeating or infusing something with a substance

transport - an exchange of molecules (and their kinetic energy and momentum) across the boundary between adjacent layers of a fluid or across cell membranes

spread, spreading - process or result of distributing or extending over a wide expanse of space

mythology - myths collectively; the body of stories associated with a culture or institution or person

dispersion, distribution - the spatial property of being scattered about over an area or volume

spreading, spread - act of extending over a wider scope or expanse of space or time

crop-dusting, spraying - the dispersion of fungicides or insecticides or fertilizer on growing crops (often from a low-flying aircraft)