Crossword Genius

In need of exercise book here? (9)

Ross

I believe the answer is:

gymnasium

I'm a little stuck... Click here to teach me more about this clue!

'book here?' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe there's an association between them I don't understand?

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for gymnasium that I've seen before include "Saying Mum (anag.)" , "Training room" , "Hall for PE" , "Place for physical exercises" , "Athletics facility" .)

I've seen this clue in The Telegraph.
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