Maps leading to Turkish capital, finally (2,4)
I believe the answer is:
at last
'finally' is the definition.
('at last' can be a synonym of 'finally')
'maps leading to turkish capital' is the wordplay.
'maps' becomes 'atlas' (printed collection of maps).
'leading to' means one lot of letters go next to another (some letters go before or lead others).
'capital' indicates taking the first letters.
The initial letter of 'turkish' is 't'.
'atlas'+'t'='AT LAST'
(Other definitions for at last that I've seen before include "Finally, after a long wait" , "Finally, after much delay" , "Where a snob worked" , "None too soon" , "Where cobbler located" .)