傍系

1. Origins, structure, and basic meaning

• Structure: 傍系(ぼうけい) means a collateral line branching off from a main line.
• Basic usage: It is used to distinguish collateral from direct lines in a family tree or to describe a branch family in a story.

2. Common pitfalls and similar expressions

• Direct and collateral lines
  • 直系(ちょっけい) is a direct line through generations, such as parent and child. 傍系 refers to a collateral family line, as with siblings or cousins.