We don't have synonyms for amu dar'ya yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are amu darya.
(n) :
Alternative spelling of Amu Darya. [A major river in Central Asia, flowing along the borders of Afghanistan, Tajikistan, Turkmenistan and Uzbekistan, emptying into the (now mostly dry) Aral Sea; known in Classical times as the Oxus.]
(n) :
Alternative spelling of Amu Darya. [A major river in Central Asia, flowing along the borders of Afghanistan, Tajikistan, Turkmenistan and Uzbekistan, emptying into the (now mostly dry) Aral Sea; known in Classical times as the Oxus.]