Enclose a twopenny piece (3)

I believe the answer is:

pen

'enclose' is the definition.
(thesaurus)

'a twopenny piece' is the wordplay.
'piece' indicates a hidden word.
'PEN' is hidden within 'twopenny'.

(Other definitions for pen that I've seen before include "International Association of poets, playwrights etc" , "Writing tool" , "See 20" , "Coop" , "Animal enclosure" .)

I've seen this clue in the Evening Standard.

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