直系

1. Origins, structure, and basic meaning

• Structure: 直系 (ちょっけい) is a noun for a direct line of descent through parents, children, and successive generations.
• Basic usage: It modifies descendants and relatives in expressions such as 直系の子孫 and 直系親族.
  • 彼は創業者の直系の子孫に当たる。 — He is a direct descendant of the founder.
  • 申請には直系親族の同意が必要だった。 — The application required the consent of a lineal relative.

2. Common pitfalls and similar expressions

• Lineal and collateral
  • 直系 is a direct ascending or descending family line, while 傍系 is a collateral line branching through siblings and their descendants.