Rabāb used to be a term for any stringed instrument.
rabāb or rabābah, an Arabic fiddle in the 10th century. Parent of the medieval European rebec or rubebe (11th-18th century Mediterranean/Balkans) and lira (like the lyre?) The ancient rabāb was the ancestor of almost all European bowed instruments. It had a membranous belly, 2-3 strings, and narrow neck. Its range was about an octave.
PERSIA Large rebab, more range than the ancient rabab. (similar instrument - kamanche or khomanche) Iraqi and Bedouin - joza, variant with coconut-shell soundbox.
CENTRAL ASIA more western, higher pitched
MUGHAL The seni rabab - wood body with resonator and six strings, no frets and traditionally no sympathetic strings.
Kabuli rabab (Afghan) - hollow wood body with gut or nylon strings.
Rabab - original ancestor. Rebab - used in gamelan. Robab or rubab - originated in Afghanistan.