名詞 primogeniture:

1. right of inheritance belongs exclusively to the eldest son

1. He inherited his father by right of his primogeniture.
   他憑著長子繼承權，繼承了他父親的財產(chǎn)。

pri.mo.gen.i.ture

n.（名詞）
The state of being the first-born or eldest child of the same parents.
長嗣身份：為同一父母的頭生子或最年長的孩子的狀況
Law The right of the eldest child, especially the eldest son, to inherit the entire estate of one or both parents.
【法律】 長嗣繼承權：最年長的孩子，尤指最年長的兒子繼承單親或雙親的所有財產(chǎn)的權利

來源：
Late Latin promôgenitôra
后期拉丁語 promôgenitôra
Latin promô [at first] from promus [first] * see per
拉丁語 promô [最初地，首先] 源自 promus [第一] *參見 per
Latin genitôra [birth] from gignere genit- [to beget] * see gen…-
拉丁語 genitôra [出生] 源自 gignere genit- [生（子女）] *參見 gen…-

【引伸】
pri.mogen.itar.y