一いっ系けい

noun

single-family lineage

Refers to a lineage or descent that is from a single family, as opposed to multiple families. Often used in historical or genealogical contexts.

• この地ち域いきの旧きゅう家かは一いっ系けいの家か系けいを守まもってきた。

  The old families of this region have preserved a single-family lineage.