Stopper somewhere in Ireland (4)

I believe the answer is:

cork

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'stopper' is the definition.
(I know that cork is a type of stopper)

I don't understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for cork that I've seen before include "It's needed for a bottle of wine" , "Stopper; Irish city" , "Irish city or county" , "Bung for a bottle" , "Tree bark from the South of Ireland?" .)

I've seen this clue in the Sydney Morning Herald.

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