retrovirus

Concise Oxford English Dictionary © 2008 Oxford University Press:
retrovirus /ˈrɛtrəʊˌvʌɪrəs/

▶noun Biology any of a group of RNA viruses which insert a DNA copy of their genome into the host cell in order to replicate, e.g. HIV.

– derivatives
retroviral adjective.

– origin 1970s: mod. L., from the initial letters of reverse transcriptase + virus.