Acquired immunodeficiency syndrome or Acquired immune deficiency syndrome (AIDS) is a disease caused by a virus called HIV.
Acquired means that people are not born with the disease. They get it after being infected with the HIV virus
Immune or Immuno- talks about the immune system. The immune system is the part of the body that fights off disease
Deficiency means not to be enough. An immuno-deficiency is a problem where the immune system is damaged and cannot fight off diseases to keep the body healthy
Syndrome is a collection of symptoms, or problems in the body. Because the immune system is damaged, and cannot fight off disease, people with AIDS get a collection of symptoms which is referred to as the "Acquired Immunodeficiency Syndrome"