The Kazakhs used this word to define the settled
Turkic tribes who inhabited the eastern and western Turkestan and who spoke in
a Turkic language and Turkified Tajiks. The word "Sart" is not the
name of a tribe or family. It was first found in the ancient book of Turks
"Kudatku Bilik." ("Blessed knowledge"). The book was
written around 1070 in Kashgar.
The word "Sart" comes from the ancient name of the river Jaxartes, the former name of the Syr-Darya. All the tribes that settled there got a name Sarti. Among the Ozbek people, the word Sart was used to define the seceded from the Kazakhs - Ozbeks, Tatars and Karakalpaks. The last tribes separated from us when we were called Kazakhs. These tribes came to the Syr-Darya and mingled there with the local Sarts and Kurama Turks. Kurama is the Kazakh settled tribes, mostly kedei (poor people), who failed to migrate in the year of the Great Tribulation ("Aktaban - shubyryndy"). The structure of the Kazakhs include the tribes: kerbushi, shahruhiya, buka, murataly, kereyt, baisu, karakytay, kalaybar, pangaz. They were engaged in arable farming when they joined sarts.
From the book of Shakarim Kudayberdy-uly "Genealogy of Turks, Kyrgyz, Kazakhs and their Khan dynasties". Translation by B. Kairbekov. Alma-Ata, Dastan JV, 1990