Wire with no piano purpose (4)
I believe the answer is:
fuse
'wire' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'no piano purpose' is the wordplay.
'no piano' becomes 'f' (I can't explain this - if you can you should believe this answer much more).
'purpose' becomes 'use' (synonyms).
'f'+'use'='FUSE'
'with' is the link.
Can you help me to learn more?
(Other definitions for fuse that I've seen before include "Unite by melting" , "Mix together" , "Join or blend to form an entity" , "Safety device in circuit" , "Meld" .)