What language or cultural background?
One possible explanation is that is it is shortened from the surname Rivinus (or Rivinius) that is a humanist latinsation of the German surname Bachmann (see, e.g.,
https://de.wikipedia.org/wiki/August_Quirinus_Rivinus )
There is also a plant named Rivina (after the above mentioned botanist). A plant name gives a girl's name, and a masculine form derived from Rivina brings us to Rivin.
This message was edited 8/25/2015, 9:09 AM