Site of beautiful marble mausoleum in Panama graveyard (4)

I believe the answer is:

agra

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'site of beautiful marble mausoleum' is the definition.
The definition suggests a singular noun which matches the answer.

'in panama graveyard' is the wordplay.
'in' indicates the answer is hidden within the clue.
'AGRA' is hidden in the letters of 'panama graveyard'.

Can you help me to learn more?

(Other definitions for agra that I've seen before include "Taj Mahal city" , "Indian masterpiece" , "vicinity of mausoleum" , "Indian city, capital of the Mogul empire until 1658" , "tourist centre" .)

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

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