finial
/ˈfaɪnɪəl/noun
1- a distinctive section or ornament at the apex of a roof, pinnacle, canopy, or similar structure in a building（建筑物的）叶尖饰, 尖顶饰。
1.1
- an ornament at the top, end, or corner of an object物件顶部（或端部、角落上的）装饰物：
ornate curtain poles with decorative finials.
带有装饰帽的华丽窗帘杆。
词源
late Middle English: from Old French fin or Latin finis 'end'.