"Acquired immunodeficiency syndrome (AIDS) is a term that applies to the most advanced stages of HIV infection. It is defined by the occurrence of any of the more than 20 life-threatening cancers or “opportunistic infections”, so named because they take advantage of a weakened immune system."
Source: WHO. 2017. "Is AIDS different from HIV?". World Health Organization Website. <https://www.who.int/news-room/q-a-detail/hiv-aids> Accessed 06 May 2020.