Family lineage (also called gia toc). The members of a lineage worship the same ancestors. They must preserve the honor, prosperity and solidarity of the extended family.
The extinction of a lineage is considered a grave sin towards the ancestors. Lineage is counted in nine degrees of relationship (cuu toc), four generations back in time from one’s own, and four forward. Going back are parents (cha, mẹ or Sino- Vietnamese phu mau), grandparents (ong, ba or to phu mau), great- grandparents (cu or tang to phu mau), and great-great-grandparents (ky or cao to phu mau). Back beyond this generation is the collective group of ancestors (to tien).
At the top of the lineage is the founder, or first ancestor (thuy to). Forward in time from one’s own generation come children (con or Sino-Vietnamese tu), grandchildren (chau, ton), great- grandchildren (chat, tang ton) and great-great-grandchildren (chut, huyen ton). Beyond this, the general term “descendants” (vien ton) is used.