Structure in Steinway shows genius (8)
I believe the answer is:
einstein
'genius' is the definition.
(as in Albert Einstein)
'structure in steinway shows' is the wordplay.
'shows' says the answer is hidden in the clue.
'EINSTEIN' can be found hidden inside 'structure in steinway'.
(Other definitions for einstein that I've seen before include "US physicist" , "Albert -, relativity physicist" , "Clever clogs finding" , "Nobel prize-winner" , "19 [BRAINY] fellow" .)