Paper required to make the article longer (3)

I believe the answer is:

pad

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'paper' is the definition.
(pad is a kind of paper)

I cannot understand how the rest of the clue works.

(Other definitions for pad that I've seen before include "Absorbent material" , "Bachelor's place?" , "Stuff the animal's foot" , "Walk softly around the apartment?" , "Batsman's protection" .)

I've seen this clue in the Evening Standard.

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