What is "behter"

Behter or Bekter (; ? - 1180) was the son of Yesugei, chief of the Kiyad clan, and a junior wife named Suchigu in some sources and Ko'agjin in others. He was also half-brother of Genghis Khan. On the death of Yesugei, Genghis, his mother Hoelun, his siblings and two half-brothers (including Bekter) were abandoned by their tribe and left to fend for themselves. Living off the land, they managed to survive. However, the older half-brothers deprived 14-year-old Temujin's (Genghis' childhood name) and his brother Qasar of their spoils. Temujin and Qasar stalked and killed Bekter. They were scolded by their mother Hoelun for that. Bekter is an Orkhon Turkic word meaning "armor".