At home, book is held back (9)

I believe the answer is:

inreserve

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'held back' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.

'at home book' is the wordplay.
'at home' becomes 'in' ('I'm in' can mean 'I'm at home').
'book' becomes 're-serve' (as in booking or reserving in advance).
'in'+'reserve'='INRESERVE'

'is' is the link.

Can you help me to learn more?

I've seen this clue in The Daily Express.

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