STOPPER, noun

1. One who stops, closes, shuts or hinders; that which stops or obstructs; that which closes or fills a vent or hole in a vessel.

2. In seamens language, a short piece of rope used for making something fast, as the anchor or cables. Stoppers are also used to prevent the running rigging from coming up, whilst the men are belaying it.

STOPPER, verb transitive To close with a stopper