Source : Webster's Revised Unabridged Dictionary (1913)

Finial \Fin"*i*al\, n. [L. finire to finish, end. See {Finish}.]
   (Arch.)
   The knot or bunch of foliage, or foliated ornament, that
   forms the upper extremity of a pinnacle in Gothic
   architecture; sometimes, the pinnacle itself.

Source : WordNet®

finial
     n : an ornament at the top of a spire or gable; usually a
         foliated fleur-de-lis