noun
Refers to a family line that has branched off from the main family, or a clan/tribe. Often used in historical or anthropological contexts.
彼は本家から分かれた支族の出身だ。
He comes from a branch family that split off from the main house.
その地域にはいくつかの支族が住んでいた。
Several tribes lived in that area.
Compound of 支 (branch, support) and 族 (family, tribe). The exact historical derivation is uncertain, but the word follows standard Sino-Japanese word formation.