Sentence:  An artificial kidney these days still means a refrigerator-sized <WSD>dialysis</WSD> machine. Such devices mimic the way real kidneys cleanse blood and eject impurities and surplus water as urine. 
Meaning of the word marked with <WSD> tags:  Utilization of this method for removal of waste products from the blood in the case of kidney failure: hemodialysis or peritoneal dialysis.