Exist as regions (5)

I believe the answer is:

areas

'regions' is the definition.
(I know this)

'exist as' is the wordplay.
'exist' becomes 'are' ('they exist' means 'they are').
'are'+'as'='AREAS'

(Other definitions for areas that I've seen before include "Spaces covered by two-dimensional surfaces" , "Localities" , "Places" , "Geographical regions" , "Zones" .)

I've seen this clue in the Evening Standard.

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