What might be compact disc? (6)

I believe the answer is:

mirror

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'be compact disc?' is the definition.
(I've seen this in another clue)

I don't understand the remainder of the clue.

(Other definitions for mirror that I've seen before include "Image reflector" , "model" , "Reflect" , "copy of > tabloid" , "Common device for reflection" .)

I've seen this clue in The Sun.

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