fer·rule
noun/ˈferuːl/
/ˈferəl/
- a piece of metal or rubber that covers the end of an umbrella or a stick to protect it
（棍杖、伞顶端的）金属包箍，橡皮包头 Word Originearly 17th cent.: alteration (probably by association with Latin ferrum ‘iron’) of obsolete verrel, from Old French virelle, from Latin viriola, diminutive of viriae ‘bracelets’.