finial

In Gothic architecture, the decorative termination of a steep triangular form, such as a gable or pinnacle. It is often carved in the form of a fleur-de-lys, and can accompany decorative foliage clumps (or crockets) running up the sides of the pinnacle below.

The finial is an architectural device, typically carved in stone and employed to decoratively emphasise the apex of a gable, or any of various distinctive ornaments at the top, end, or corner of a building or structure.

The finial can also function as a lightning rod, and was once believed to act as a deterrent to witches on broomsticks attempting to land on one's roof.

Flagpoles

A "ball-style" finial is commonly mounted to the top of a stationary flagpole. A related and less pleasant version says the finial should have a bullet, knife, and matches so the last surviving soldier can continue fighting (with the knife), and if need be destroy the flag with matches (to prevent it from being captured), and take his own life with the bullet.

Straw Animals on the Ridges of Thatched Cottages

Finial is also a term given to makers of straw animals for the ridges of thatched cottages.