Good grounds for holding sports (6)

I believe the answer is:

stadia

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'good grounds' is the definition.
'stadia' can be an answer for 'grounds' (I've seen this before). I'm unsure of the 'good' bit.

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for stadia that I've seen before include "Big venues" , "Bowls" , "major venues" , "Athletics grounds" , "Sports arenas" .)

I've seen this clue in The Irish News and The Globe and Mail.

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