Why is AIDS considered to be a "Syndrome" and not a disease?

Explanation

AIDS is acquired immuno deficiency syndrome, caused by human immuno deficiency virus. When a group of symptoms occur together in the existence of a particular disease, it is known as syndrome. Person infected with HIV virus is prone to various pathogens because the immune system becomes weak. There is no particular symptom of the disease in the preliminary period, symptoms occur after many years of attack of virus.