HIV is the virus that causes AIDS.
H - Human: because this virus can only infect human beings.
I - Immune-deficiency: because the effect of the virus is to create a deficiency, or a failure to work properly, within the body's immune system.
V - Virus: because this organism is a virus, which means one of its characteristics is that it is incapable of reproducing by itself. It reproduces by taking over the machinery of the human cell.
A - Acquired: because it is a condition one must acquire or get infected with; not something transmitted through the genes
I - Immune: because it affects the body's immune system, the part of the body which usually works to fight off germs such as bacteria and viruses
D - Deficiency: because it makes the immune system deficient (makes it not work properly)
S - Syndrome: because someone with AIDS may experience a wide range of different diseases and opportunistic infections