stopper

Short definition from Wiktionary

Noun

1. 1
   Someone or something that stops something.
2. 2
   A type of knot at the end of a rope, to prevent it from unravelling.
3. 3
   A bung or cork.
4. 4
   Goalkeeper.
5. 5
   In the commodity futures market, someone who is long (owns) a futures contract and is demanding delivery because they want to take possession of the deliverable commodity.
6. 6
   A train that calls at all or almost all stations between its origin and destination, including very small ones.
7. 7
   Any of several trees of the genus Eugenia, found in Florida and the West Indies.
8. 8
   A short rope for making something fast.
9. 9
   A playspot where water flows back on itself, creating a retentive feature.

Verb

1. 1
   To close a container by using a stopper.