Turkestan
noun
a vast region in western and central Asia, east of the Caspian Sea: includes territory in the south central part of Xinjiang province in China Eastern Turkestan or Chinese Turkestan, a strip of northern Afghanistan, and the area Russian Turkestan comprising the republics of Kazakhstan, Kirghizia (Kyrgyzstan), Tadzhikistan (Tajikistan), Turkmenistan, and Uzbekistan.
