I. dīˈaləsə̇s noun
( plural dialy·ses -əˌsēz)
Etymology: New Latin, from Greek, separation, dissolution, from dialyein to break apart, dissolve (from dia- + lyein to loosen) + -sis — more at lose
1. : the separation of substances in solution by means of semipermeable membranes (as of parchment, cellophane, or living cells) through which the smaller molecules and ions diffuse readily whereas the larger molecules and colloidal particles diffuse very slowly or not at all, such separations being important in nature (as in living organisms and in soils) and having many applications (as in blood fractionation or in the recovery of sodium hydroxide in the manufacture of viscose) — used especially of the separation of noncolloids from colloids (as proteins); see electrodialysis ; compare osmosis , ultrafiltration
2. botany : the separation of parts which are normally united especially in the same floral whorl
II. noun
: either of two medical procedures to remove wastes or toxins from the blood and adjust fluid and electrolyte imbalances by utilizing the different rates at which substances diffuse through a semipermeable membrane:
a. : the process of removing blood from an artery (as of a kidney patient), purifying it by dialysis, adding vital substances, and returning it to a vein — called also hemodialysis
b. : a procedure performed in the peritoneal cavity in which the peritoneum acts as the semipermeable membrane