Crossword Genius

Some European schools keep training equipment in these (10)

Ross

I believe the answer is:

gymnasiums

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'some european schools' is the definition.
The answer and definition can be both man-made objects as well as being plural nouns.
Perhaps there's an association between them I don't understand?

I cannot understand how the rest of the clue works.

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I've seen this clue in The Irish Times.
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