Pound postage (5)

I believe the answer is:

stamp

This clue is a double definition.

'pound' is the first definition.
(thesaurus)

'postage' is the second definition.
(I know that postage can be written as stamp)

(Other definitions for stamp that I've seen before include "Validation for a letter - tread heavily" , "Postal token" , "Hallmark" , "Use a die; character" , "Impress (a pattern)" .)

I've seen this clue in The Irish News and The Globe and Mail.

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