部族 means "tribe" or "clan" and refers to a social group bound by shared ancestry, culture, or territory. It is commonly used in historical contexts when discussing ancient peoples and their conflicts.
这个地区曾经住着许多不同的部族。
zhège dìqū céngjīng zhù zhe xǔduō bùtóng de bùzú.
Many different tribes once lived in this region.
两个部族之间为了水源发生了冲突。
liǎng ge bùzú zhījiān wèile shuǐyuán fāshēng le chōngtū.
The two tribes came into conflict over water resources.
那本书讲的是古代草原部族的故事。
nà běn shū jiǎng de shì gǔdài cǎoyuán bùzú de gùshì.
That book tells the story of ancient grassland tribes.