Want to turn the key to enter the home (4)
I believe the answer is:
need
'want' is the definition.
(I know that want can be written as need)
'turn the key to enter the home' is the wordplay.
'turn' is a reversal indicator.
'the key' becomes 'E' (musical key).
'to enter' indicates putting letters inside.
'the home' becomes 'den' (an animal's home).
'e' placed into 'den' is 'deen'.
'deen' backwards is 'NEED'.
'to' acts as a link.
(Other definitions for need that I've seen before include "Rely on" , "destitute state" , "Cry out for - prerequisite" , "Lack - demand" , "Want - require(ment)" .)