sub-tribe       
noun [ C ] (also subtribe) uk/ˈsʌbˌtraɪb/ us/ˈsʌbˌtraɪb/
 子部落;次级部落;小部落
a tribe (= a group of people who live together and share a culture, language, etc.) that forms part of a larger tribe
  The business is owned and run by a Maori sub-tribe. 该企业由毛利人的一个小部落拥有和经营。 
 One mountain in the area belonged to a subtribe of the main tribe. 该地区有座山属于主部落的一个子部落所有。 
 - More examples
 - In former times, each village formed its own sub-tribe, with its own chief.
 - It is difficult for outsiders to understand the hidden history of every tribe and sub-tribe.
 - The head of the family was obedient to his sub-tribe, which in turn was obedient to the tribe.
 - There is no reference to this subtribe in any of the literature of the region.