re-fastener
nounUK /ˌriːˈfɑːsənə/
US /ˌriːˈfæsənər/
A thing that closes something again after it was opened.
The re-fastener on my backpack keeps the flap shut.
OTHER MEANINGS
2. A person who fixes something back in place.
The re-fastener tightened the loose bolt on the gate.
3. A tool used to attach something again.
He used a re-fastener to put the sign back on the wall.
4. A device that keeps a seatbelt locked again after use.
The car's re-fastener clicked when she buckled up.