The Human Immunodeficiency Virus type-1 (HIV) belongs to the Family Retroviridae.
The core of a retrovirus (including HIV) contains RNA, which encodes the genetic information of the virus, and an enzyme known as reverse transcriptase. Reverse transcriptase enables the virus to convert RNA to double-stranded DNA (the opposite of the normal process of transcription where double-stranded DNA is converted to single-stranded RNA).
Because of this reverse process, HIV is known as a retrovirus; retro implying reverse.
