Corresponding material in rubbish promos is rejected (8)

I believe the answer is:

isomorph

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'corresponding material' is the definition.
The definition suggests a singular noun which matches the answer.

'in rubbish promos is rejected' is the wordplay.
'in' indicates the answer is hidden within the clue.
'rejected' shows that the letters should be reversed in order.
'hpromosi' is hidden in the letters of 'rubbish promos is'.
'hpromosi' backwards is 'ISOMORPH'.

Can you help me to learn more?

(Other definitions for isomorph that I've seen before include "one exhibiting corespondence" , "unchanged in shape" .)

I've seen this clue in The Times.

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