cork

noun

1.
outer bark of the cork oak; used for stoppers for bottles etc.
Derived from:
cork
2.
(botany) outer tissue of bark; a protective layer of dead cells
phellem
3.
the plug in the mouth of a bottle (especially a wine bottle)
shive bottle cork
Derived from:
cork corky
4.
a small float usually made of cork; attached to a fishing line
bob bobber bobfloat