"Lineal" is a word in LAW AND LEGAL, ENGLISH

That which comes in a llne; especlally a direct line, as from father to son. Collateral relationship ls not called “lineal,” though the expresslon “collateral line," ls not unusual

Inheriting by direct descent; having the right by direct
descent to succeed (to).

Composed of lines; delineated; as, lineal designs.

Descending in a direct line from an ancestor; hereditary;
derived from ancestors; -- opposed to collateral; as, a lineal descent
or a lineal descendant.

In the direction of a line; of or pertaining to a line;
measured on, or ascertained by, a line; linear; as, lineal magnitude.