Usual memo strangely remains to be seen (9)

I believe the answer is:

mausoleum

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'remains to be seen' is the definition.
I can't tell whether this definition defines the answer.

'usual memo strangely' is the wordplay.
'strangely' indicates anagramming the letters.
'usual'+'memo'='usualmemo'
'usualmemo' anagrammed gives 'MAUSOLEUM'.

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(Other definitions for mausoleum that I've seen before include "Sepulchre" , "Great tomb - usual memo (anag)" , "Housing for a tomb" , "One may lie impressively in this" , "Wonder of World tomb" .)

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