Turkistan vs Turkestan

Turkistan and Turkestan both are nouns.

Word	Noun	Adjective	Verb	Adverb
Turkistan	Yes	No	No	No
Turkestan	Yes	No	No	No

As nouns, Turkistan and Turkestan are synonyms defined as:

Turkistan and Turkestan: a historical region of central Asia that was a center for trade between the East and the West

Turkistan (noun)	Turkestan (noun)
a historical region of central Asia that was a center for trade between the East and the West	a historical region of central Asia that was a center for trade between the East and the West