Here's something that you might find useful.
MILITARY TERMS IN MONGOLIAN:
Divisions:
Arbat - troop of ten
Zuut (Jigaut) - troop of one hundred
Myanggat - troop of one thousand ** a political unit of 1000 households, not an exact number of men **
Tümen - troop of ten thousand ** actualy means 'division' any large unit. Temuljin set up permanent units of 10,000 housholds. Field strength was typically 5,000-7,000 men **
Ikhe Tsereg - army
Units:
Tsereg - soldier ** from cherig, not originally Mongol term, used primaraly for non Mongol troops **
Morit Tsereg - cavalry
Yavgan Tsereg - infantry
Shadar Tsereg - imperial troops, same as:
The best English term to use for keshik is 'household', it refers to the personal following of a khan, prince etc.. Temuljins was responsible for procurement, storage and issue of lannces, shields, artillery and arrows. There were also military units included (night guard, arrow guard, day guard and heroes - multiple units of the last two). By Temuljins death, his included 18 mingams.
Heshigten (not just Keshik) - imperial bodyguard, which divided into:
Hebteul - night guards
Horchin - seems like they guarded the perimeter of the emperor's ordon (horde) ** the actual bodyguards who attended the leader **
Torguud - the rest of heshigten
Uruud (Urugud), Mangud - two famous tribes, from the SHoM
Mangudai - old Mongol 'god belonging' used to describe long range scouts. Sadly many western historians assume that the name must mean suicide troop or some such and prattle rubbish **
Ranks:
Nöhör/Nukher - some noyon's personal guard type warriors
Noyon - noble (someone who has people/troops that he "owns") ** in Temuljins time this was limited to members of the ruling clan, later others were raised to this level **
Taish - second in command after the Khan (not Khagan) after corrupted into taij - a title close to, say, marquis
Bahadur - probably meant general, otherwise, distinguished warrior, the elite, a veteran ** not 'general', not a rank as such though many generals were bahadur, literally hero, the title was honoriffic and could be bestowed on any persion who showd great bravery in battle. It also applied to members of the bahadur unit of the keshik. Later it was expanded to be a generic name for elite guard units **