Ottoman rulers once used the word Turk mainly for Anatolian peasants
In the nineteenth-century Ottoman Empire, the elite called themselves Ottomans, and Türk was a label for Anatolian villagers. Only as European nationalism spread did the name gain prestige, until the Young Turks embraced it and it went on to name a new republic. Nobody is quite sure where the word itself came from.
Turks are the largest Turkic ethnic group, forming most of the population of Turkey and Northern Cyprus, with long-established communities across former Ottoman lands and Turkmen populations in countries such as Iraq and Syria. Turkey's constitution, in Article 66, defines a Turk simply as a citizen, though an estimated 70 to 75 percent of the country's people are ethnically Turkish. Most are Sunni Muslims.
The name's origin is an open puzzle. Chinese chronicles recorded it as Tujue, referring to the Göktürks, and the earliest Turkic spelling appears in the Orkhon inscriptions of the Second Turkic Khaganate. Roman writers such as Pliny the Elder listed peoples called Tyrcae near the Sea of Azov, though one archaeologist dismissed that as a miscopying. Within Turkic languages the word can mean strong, ripe or in the prime of life.
The language itself traces back to Central-East Asia, perhaps the Altai-Sayan region, Mongolia or Tuva, where early speakers moved from mixed hunting and farming to nomadic herding. Anatolia, by contrast, had passed through Hittite, Hellenistic, Roman and Byzantine hands. Change came with the Seljuks, who absorbed much Persian culture, took Baghdad by 1055 and beat the Byzantines at Manzikert in 1071. Byzantium's appeals to the West helped set off the First Crusade, and the Seljuks founded the Sultanate of Rum in 1077, governing from Konya from 1097. By the 12th century Europeans were already calling the region Turchia.
Mongol armies crushed the Seljuks at Köse Dağ in 1243 and invaded again in 1256. After 1277 central authority crumbled, and Turkoman lords carved out small principalities called beyliks in western Anatolia, one of which grew into the Ottoman state. Much later, Mustafa Kemal Atatürk defined the nation as the people who founded the Turkish republic, bound by shared political life, language, homeland, origin, history and morals.
Source: Turkish people