𐱅𐰇𐰏𐰠𐱅𐰤

Uncertain, however there have been multiple attempts at understanding the etymology.

1. Some connect the first part of the name to Proto-Turkic *tökül- (“to be poured”), the passive form of *tök- (“to pour”), however one should've expected -k- rather than -g- (cf. Turkish dökülmek) and there is no viable morphological way to derive it as there is no *-tün suffix.
2. Some read it as tügül:tün and explain it as "not Tün", the first part coming from a hypothetical Proto-Turkic *tegül, however this is etymologically and phonetically improbable.^[1]
3. Li suggests that the second element is borrowed from Middle Chinese 屯 (MC trwin|dwon, “village”) and reads it as "The Village of Tögül" although the first part still remains obscure.

Li also put forward the idea that it was used as the word for the Hetao region.

𐱅𐰇𐰏𐰠𐱅𐰤 (tögültün)

1. the Hetao Region
   • 8th century CE, Kültegin Inscription, S6-7:

     𐰋𐰼𐰘𐰀:𐰲𐰆𐰍𐰖:𐰘𐰃𐱁:𐱅𐰇𐰏𐰠𐱅𐰤:𐰖𐰔𐰃:𐰸𐰆𐰣𐰖𐰃𐰤:𐱅𐰃𐰾𐰼:𐱅𐰇𐰼𐰜:𐰉𐰆𐰑𐰣:𐰇𐰠𐰾𐰚𐰏

     bériye:čuɣay:yïš:tögültün:yazï:qonayïn:téser:türük:bodun:ölsikig

     If you intend to settle on the Yin mountains and on the Hetao region's plain in the south, O Turkic people, you will die!

• Aydın, Erhan (2016) “Tögültün”, in Eski Türk Yer Adları (in Turkish), Istanbul: Bilge Kültür Sanat, →ISBN, page 148
• Tekin, Talât (1968) “tögültün”, in A Grammar of Orkhon Turkic (Uralic and Altaic Series; 69), Bloomington: Indiana University, →ISBN, page 384