You can link it with a European capital (3)
I believe the answer is:
tie
'capital' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'you can link it with a european' is the wordplay.
'you can' becomes 'i' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'link' is an insertion indicator (the inserted material links two sets of letters).
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'with' means one lot of letters go next to another.
'a european' becomes 'E' (abbreviation e.g. EU).
't'+'e'='te'
'i' put into 'te' is 'TIE'.
Can you help me to learn more?
(Other definitions for tie that I've seen before include "Drawn score" , "11 [KNOT]" , "'Fasten, with string say (3)'" , "Secure (with string)" , "Equal score" .)