The slave, whose hairline started at his eyebrows' level, was called Mùgúlǘ (木骨閭) - "bald-headed" in the Xianbei language.

Alexander Vovin proposes that Mùgúlǘ (木骨閭), in reconstructed Middle Chinese *muwk-kwot-ljo, transcribed Tuoba Xianbei *moqo-lo ~ muqo-lo 'bald head', which is analysable as 'one [who/]which has cut-off/fallen-off [hair]' and cognate with Mongolic lexical items like Written Mongolian moɣutur ~ moqutur 'blunt, hornless, bald tail' (cf.

Chinese gloss: 禿尾 'bald tail'), moqu-ɣar, Middle Mongol muqular 'hornless', moqo-dag 'blunt'; all of those are from Proto-Mongolic *muqu 'to be cut off, break off, fall off', which in turn would produce the semantic variation 'blunt ~ hornless ~ hairless ~ bald'.

Golden additionally proposes connection with Turkic uğurluğ "feasible, opportune", later "auspicious fortunate" or oğrï "thief", an etymology more suited to the dynasty's founder's activities; additionally Yujiulü may be comparable to Middle Mongolian uğuli "owl" (> Khakha ууль uul'), as personal names based on bird names are common in Mongolic.

[7] Chinese author Wang Anyi wrote that her mother Ru Zhijuan might be descended from Rouran.