Noun | 1. | dialysis - separation of substances in solution by means of their unequal diffusion through semipermeable membranes chemical analysis, qualitative analysis - the act of decomposing a substance into its constituent elements pheresis, apheresis - a procedure in which blood is drawn and separated into its components by dialysis; some are retained and the rest are returned to the donor by transfusion haemodialysis, hemodialysis - dialysis of the blood to remove toxic substances or metabolic wastes from the bloodstream; used in the case of kidney failure osmosis - (biology, chemistry) 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 |