Along their long history, Turkic languages got into contact with numerous other languages, amongst which was also Chinese. Many Chinese Buddhist works were translated into Uighur, and, as a matter of course, these translations activated loans in Uighur from Chinese. Several studies have dealt with the Chinese loans in Uighur, and most of them regard Uighur čog ‘glowing heat, flame; splendour’ as a word of Chinese origin. The present paper carefully investigates the word čog and the words related to it in Old Turkic, and comes to the conclusion that the Chinese derivation of the word is not so obvious, since that explanation is aggravated by serious difficulties. Instead, on the basis of Turkic linguistic data, the author offers new ideas for explaining the Uighur word čog.