Tumen, or tümen ("unit of ten thousand";[1] Old Turkic: tümän; Mongolian: Түмэн, tümen;[2][3] Turkish: tümen; Hungarian: tömény), was a decimal unit of measurement used by the Turkic and Mongol peoples to quantify and organize their societies in groups of 10,000. A tumen denotes a tribal unit of 10,000 households, or a military unit of 10,000 soldiers.
English Orientalist Sir Gerard Clauson (1891-1974) defined tümän as immediately borrowed from Tokharian tmān, which according to Edwin G. Pulleyblank might have been etymologically inherited from Old Chinese tman or 萬.[4]