Negative-strand RNA virus: Also known as an antisense-strand RNA virus, a virus whose genetic information consists of a single strand of RNA that is the negative or antisense strand which does not encode mRNA (messenger RNA). Examples of negative-strand RNA viruses include influenza virus, measles viruses, and rabies virus.
There are two types of RNA viruses. Some are positive in that they have a "sense" strand of RNA (coded information about how to build proteins) as their genetic material. And other RNA viruses tare negative in that they have an "antisense" strand (the paired opposite of the coded information). Negative-strand or antisense-strand RNA viruses are as opposed to positive-strand or sense-strand RNA viruses.
See also: Positive-strand RNA virus.