Semu refers to a political class within Imperial China, specifically during the Yuan dynasty. Rather than being a self-defined ethnic group, the term was originally an exonym used to categorize various Central and East Asian peoples who came to serve the Chinese political system as foreign experts.
The Semu were one of four distinct castes that divided Yuan society, alongside the Mongols, Hanren, and Nanren. This diverse group included Buddhist Turpan Uyghurs, Tanguts, and Tibetans, as well as Church of the East Christian tribes such as the Ongud and various Turkic Muslim peoples, including Khwarazmians.