Strictly speaking, the common name "Göktürk" is the Anatolian Turkish form of the historical ethnic group's endonym: which was attested as , or . They were known in Middle Chinese historical sources as the "Tūjué" (; reconstructed in Middle Chinese as romanized: *"dwət-kuɑt" > "tɦut-kyat"). According to Chinese sources, Tūjué meant "combat helmet" (), reportedly because the shape of the Altai Mountains, where they lived, was similar to a combat helmet. Róna-Tas (1991) pointed to a Khotanese-Saka word, "tturakä" "lid", semantically stretchable to "helmet", as a possible source for this folk etymology, yet Golden thinks this connection requires more data.