形容詞 lineal:

1. in a straight unbroken line of descent from parent to child
   同義詞：direct
2. arranged in a line

lin.e.al

adj.Abbr. lin.（形容詞）縮寫 lin.
Belonging to or being in the direct line of descent from an ancestor.
直系的：屬于或成為祖先的直系后代
Derived from or relating to a particular line of descent; hereditary.
遺傳性的：從一特定的直系后代獲得的或相聯(lián)系的；遺傳性的
Linear.
直線的

來(lái)源：
Middle English
中古英語(yǔ)
from Old French
源自 古法語(yǔ)
from Late Latin lone3lis [consisting of lines]
源自 后期拉丁語(yǔ) lone3lis [由線構(gòu)成的]
from Latin lonea [line] * see line
源自 拉丁語(yǔ) lonea [線] *參見 line

【引伸】
lin.eally
adv.（副詞）