HIV - The Human Immunodeficiency Virus, more commonly known as HIV, is a retrovirus that cannot be cleared by your immune system, instead attacking it and weakening it over time. HIV attacks the CD4 cells that help you fight illness and uses them to replicate itself. Left untreated, the HIV virus will break down your immune system, leading to Acquired Immunodeficiency Syndrome, better known as AIDS.
AIDS - Acquired Immunodeficiency Syndrome is the final stage of HIV (Human Immunodeficiency Virus) and is diagnosed when your immune cells drop below a certain level or when certain cancers or other infections are diagnosed. You will need acute medical care at this stage, as AIDS can quickly lead to death without medical intervention.