Field ball (6)

I believe the answer is:

sphere

I believe this clue is a double definition.

'field' is the first definition.
(I know that field can be written as sphere)

'ball' is the second definition.
(I've seen this before)

(Other definitions for sphere that I've seen before include "Vault of heaven" , "Globe or ball" , "Round object" , "Perfect round" , "Area of activity" .)

I've seen this clue in The Telegraph.

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