retainerstrap
nounUK /rɪˈteɪnə stræp/
US /rɪˈteɪnər stræp/
A small band that holds something in place.
He used a retainer strap to keep his glasses from falling off.
OTHER MEANINGS
2. A strap that keeps a dental retainer attached.
She wore a retainer strap so her retainer wouldn't get lost at lunch.
3. A strap that secures a part in a machine.
The mechanic replaced the retainer strap on the engine cover.
4. A band that holds a helmet or cap on the head.
The bike helmet's retainer strap kept it snug during the ride.