It is the singular possessive form of the noun coaster (inanimate possessive). Example: The coaster's cork bottom became stuck to the table.
The cork side goes down (on the table) to prevent the coaster from sliding, and marring wooden furniture. Actually if the drink has a lot of condensation the cork goes up so the liquid can be soaked up in the cork and not dripping all over your furniture.
Here is a list of interesting uses of cork coasters: Stamps, fridge magnets, Trivet, keychain, bathmat, mini succulent garden, coaster, jewelry organizer and so much more.
Cork comes from a cork tree :]
cork comes from a cork tree
cork is a type of color like brownish
'cork' is the bark of the cork oak tree.
Cork for bottles is made from cork trees.
Cork is a part of the bark on a Cork Oak Tree.
Cork comes from trees which are eukaryotic
it is heavier and more aerodynamic
The cork master is the master of the cork because he knows which wine goes with fish or pork...