Spheres, it seems, can be flat! (6)

I believe the answer is:

fields

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'spheres' is the definition.
('field' can be a synonym of 'sphere')

I can't explain the rest of the clue.

(Other definitions for fields that I've seen before include "Cleared areas of land" , "Cleared tracts of land" , "Deals with" , "Enclosed pieces of land" , "See 25 Down" .)

I've seen this clue in the Evening Standard.

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