名词

1. (尤指衣服上的)扣子，拉链，钩扣，紧固物，扣件
A fastener is a device such as a button, zip, or small hook that fastens something, especially clothing.

1. restraint that attaches to something or holds something in place

Synonym: fasteningholdfastfixing

2. a person who fastens or makes fast

e.g. he found the door fastened and wondered who the fastener was