The name `` Amu '' is said to have come from the medieval city of '' Āmul '' , ( later , Chahar Joy/Charjunow , and now known as Türkmenabat ) , in modern Turkmenistan , with `` Darya '' being the Persian word for `` river '' .
The name `` Amu '' is said to have come from the medieval city of '' Āmul '' , ( later , Chahar Joy/Charjunow , and now known as `` Türkmenabat '' ) , in modern Turkmenistan . `` Darya '' is the Persian word for `` river '' .