Source : Webster's Revised Unabridged Dictionary (1913)

Lineal \Lin"e*al\ (l[i^]n"[-e]*al), a. [L. linealis belonging to
   a line, fr. linea line: cf. F. lin['e]al. See 3d {Line}.]
   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.
                                                  --Locke.

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

            For only you are lineal to the throne. --Dryden.

   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.

   {Lineal measure}, the measure of length; -- usually written
      {linear measure}.