Human immunodeficiency virus. A non-taxonomic and historical term referring to any of two species, specifically hiv-1 and/or hiv-2. Prior to 1986, this was called human T-lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV). From 1986-1990, it was an official species called HIV. Since 1991, HIV was no longer considered an official species name; the two species were designated hiv-1 and hiv-2.