noun. An illness characterized by the building up of amyloid within bodily tissues. Amyloid is an involved starchy protein compound. It is thought that it results from immune-deficiency diseases. Amyloidosis is at some point entirely detrimental because it impedes the regular operations of tissues, causing tumors to grow in the liver, respiratory tracts, kidneys, and various other organ systems. Primary amyloidosis takes place in the inexistence of any other illnesses, whereas secondary amyloidosis is correlated with ongoing illnesses.