Finial

архитектура фиал (завершающее украшение шпиля)

Англо-русский научно-технический словарь

Finial

noun Etymology: Middle English, from final, finial final 1. a usually foliated ornament forming an upper extremity especially in Gothic architecture 2. a crowning ornament or detail (as a decorative knob)

Merriam-Webster's Collegiate Dictionary