a decorative object at the top, end, or corner of something such as a post, fence, gate, etc.

中文解释

(帘杆的)装饰头;（柱顶、栅栏头、大门顶的）饰物 The curtain rod is made of wrought iron with ornate finials. 窗帘杆由锻铁制成，饰有华丽的尖顶。