Lineal /(lĭn"ē̇*al)/

Lin·e·al

Lineal

a.
  1. Descending in a direct line from an ancestor; hereditary; derived from ancestors; -- opposed to collateral; as, a lineal descent or a lineal descendant.
    The prime and ancient right of lineal succession.
  2. Inheriting by direct descent; having the right by direct descent to succeed (to).
    For only you are lineal to the throne.
  3. Composed of lines; delineated; as, lineal designs.
  4. In the direction of a line; of or pertaining to a line; measured on, or ascertained by, a line; linear; as, lineal magnitude.

Phrases & Compounds
Lineal measure
the measure of length; -- usually written linear measure.