AIDS - HIV

AIDS stands for Acquired Immune Deficiency Syndrome:
Acquired means you can get infected with it;
Immune Deficiency means a weakness in the body's system that fights diseases.
Syndrome means a group of health problems that make up a disease.

AIDS is caused by a virus called HIV, the Human Immunodeficiency Virus. If you get infected with HIV, your body will try to fight the infection. It will make "antibodies", special molecules that are supposed to fight HIV.