Finial

An ornamental terminal feature on an otherwise functional object; a flourish, often curly in character. Examples of finials: the fancy knob at the end of a curtain rod; the curlicue on top of an architectural structure or a piece of furniture; the curve at the end of the main stroke of a character in some italic fonts.

Also, the highly functional spikes one often finds on top of the merlons of a crenellated wall. These don't only look badass, but could serve as anchors for temporary wooden superstructures, or hoardings, during siege. Also, one could stick a long spear between two of them without anyone being able to swing back with a sword because they would get in the way. However, the merlons are often too high for this maneuver.

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.

© Webster 1913.