A bit of information here:

http://www.organistrum.com/organistrum_uk.htm

(Though I think we may ignore the Biblical references...)

Beware of Monique's link above unless you're fond of big-breasted Russian women looking for marriage...

The name is also likely applied to giegenwerk type instruments, also bowed with a wheel but, unlike the monophonic hurdy-gurdy, using one string per note, like this beast:

https://www.youtube.com/watch?v=oRIF_undL8Q