The Rebab is a traditional Egyptian fiddle, dating back to around the 8th century. It has one string, which is strung down and then up the instrument, effectively making two strings. It’s played with a horsehair bow, the hair being held taught by the right hand fingers. The body of the instrument is usually made from half a coconut shell, covered by parchment or sheepskin.
Rebab fiddle and bow
Rebab Player
Here’s video of a rebab being played:
Here’s an Egyptian band featuring several Rebab players: