We don't have synonyms for sistan yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are sista, seistan and istan.
(n) :
A province in eastern Iran; in full, Sistan and Baluchestan.
(n) :
(historical) A geographic region of the eastern Iranian Plateau in eastern Iran and southern Afghanistan, extending into southwestern Pakistan; inhabited by the Scythian Saka tribe between the 2nd century BCE and 1st century CE.
(n) :
A province in eastern Iran; in full, Sistan and Baluchestan.
(n) :
(historical) A geographic region of the eastern Iranian Plateau in eastern Iran and southern Afghanistan, extending into southwestern Pakistan; inhabited by the Scythian Saka tribe between the 2nd century BCE and 1st century CE.