finial in Japanese

(architectural element) Especially in Gothic architecture: an ornament, often in the form of a bunch or knot of foliage, on the peak of the gable of a roof, a pediment, a pinnacle, etc.

(by extension) Any decorative fitting on the corner, end, or top of an object such as a canopy, a fencepost, a flagpole, a curtain rod, or the newel post of a staircase.