1. medical filtering process: the process of filtering the accumulated waste products of metabolism from the blood of a patient whose kidneys are not functioning properly, using a kidney machine
2. separation of substances from solution: the separation of dissolved substances from a solution by allowing the solution to diffuse through a semipermeable membrane
[Mid-19th century. Via Latin, "set of propositions without a connecting conjunction" < Greek dialusis "separation, loosening" < luein "loosen"]