natural action - a process existing in or produced by nature (rather than by the intent of human beings); "the action of natural forces"; "volcanic activity"physical process, process - a sustained phenomenon or one marked by gradual changes through a series of states; "events now in process"; "the process of calcification begins later for boys than for girls" radiation - the spread of a group of organisms into new habitats absorption - (physics) the process in which incident radiated energy is retained without reflection or transmission on passing through a medium; "the absorption of photons by atoms or molecules" acidification - the process of becoming acid or being converted into an acid adiabatic process - (thermodynamics) any process that occurs without gain or loss of heat aeration - the process of exposing to air (so as to purify); "the aeration of the soil" capture - any process in which an atomic or nuclear system acquires an additional particle capture - a process whereby a star or planet holds an object in its gravitational field centrifugation - the process of separating substances of different densities by the use of a centrifuge chromatography - a process used for separating mixtures by virtue of differences in absorbency concretion - the formation of stonelike objects within a body organ (e.g., the kidneys) condensation - the process of changing from a gaseous to a liquid or solid state convection - (meteorology) the vertical movement of heat or other properties by massive motion within the atmosphere decay - the process of gradually becoming inferior desorption - changing from an adsorbed state on a surface to a gaseous or liquid state diffusion - (physics) the process in which there is movement of a substance from an area of high concentration of that substance to an area of lower concentration drift - the gradual departure from an intended course due to external influences (as a ship or plane) ecesis, establishment - (ecology) the process by which a plant or animal becomes established in a new habitat extinction - the reduction of the intensity of radiation as a consequence of absorption and radiation extraction - the process of obtaining something from a mixture or compound by chemical or physical or mechanical means feedback - the process in which part of the output of a system is returned to its input in order to regulate its further output filtration - the process whereby fluids pass through a filter or a filtering medium flocculation - the process of flocculating; forming woolly cloudlike aggregations flow - any uninterrupted stream or discharge formation - natural process that causes something to form; "the formation of gas in the intestine"; "the formation of crystals"; "the formation of pseudopods" fossilisation, fossilization - the process of fossilizing a plant or animal that existed in some earlier age; the process of being turned to stone inactivation - the process of rendering inactive; "the gene inactivation system"; "thermal inactivation of serum samples" ion exchange - a process in which ions are exchanged between a solution and an insoluble (usually resinous) solid; widely used in industrial processing |