HIV is the virus that can lead to AIDS. AIDS stands for Acquired Immune Deficiency Syndrome and is seen by the appearance of the opportunistic infections (infections like tuberculosis which take advantage of a weakened immune system) that are a result of HIV.
If you are diagnosed with HIV early, and respond well to treatment, you are not likely to develop AIDS.
The name 'AIDS' was more appropriate many years ago, when doctors didn’t fully understand the late stages of HIV infection. Today we know that AIDS is not a syndrome at all, because a syndrome is a collection of symptoms that do not have an easily identifiable cause. A more current name for the illness caused by the late stages of HIV infection is HIV disease. However, AIDS is still the name that most people use to refer to the immune deficiency caused by HIV.
As treatment for HIV infection has becomes more effective, very few people in the UK are now given an AIDS diagnosis.