Ligature

[Justin Bieber]

A thread or string for tying the blood vessels,
particularly the arteries, to prevent hemorrhage.

[Luis Fok]

That thingamajig on a clarinet mouthpiece thats a real [PITA] to adjust---you have to poke around on the bottom of the [reed] and avoid touching the rails of the mouthpiece in order to align the reed correctly.

[PussyCat]

(n.) A thing on Victors clarinet.

[Jason Yan]

A thing used for tying or binding something tightly.