There are more than hundred english-english dictionaries in the world. According to merriam-websters website: Webster's Third New International Dictionary, Unabridged, together with its 1993 Addenda Section, includes some 470,000 entries.
Most commonly, HIV infection is spread by having sex with an infected partner. The virus can enter the body through the lining of the vagina, vulva, penis, rectum, or mouth during sex. Although vaginal and anal intercourse are the primary risk factors, oral sex transmission is also possible.
There are two types of HIV; they are HIV-1 and HIV-2 and they have many subtypes. HIV-1 is the cause of the current worldwide pandemic while HIV-2 is found in west Africa but rarely elsewhere. HIV-2, which is transmitted in the same ways as HIV-1, causes AIDS much more slowly than HIV-1. HIV-1 resulted from human infection by SIVcpz that infects chimpanzees and HIV-2 resulted from infection by SIVsmm harbored by sooty mangabeys. HIV-2 is closely related to the SIV found in west Africa.